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Stan Bray introducesthe fascinating world ofhorology to the complete bK inner.This bookexplainsth1& ofthe clockmakerand provides generaldetails ofclock construction including layoutofwheels and esc a numberofthe Iatterbeing described. kn
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Introduction thc work. A lthough a special workshop is not rtlquiredl one thing that Bri11 not do is to work in a uxlrkshop that is fulI of svvarf and ot11cl- rubbish. a 'Xtlcepting that ' we cannot alsvays llaN' e a clinically elcan plaklc in Nvhich to operate,partictllarly if it scrvkls st psr tlralpurposes,it is still possible to lllake a clean area for spccial tlsu- alld tl1is should be a priority.A tlorneroftht lNvorkshop can bt ltrlcalled ll1 ld Llny oil01 -grease lying ()11tht ? bench su abbcd off Keep this area clean NvlliI( ) clock nlaking operationsal v in progrcss.ltis a good idkla to 1' 11aktl a false top for the svorkbench and coveritw ith baize ora A lthough clocks come in a11sorts of sinaiIarnaaterialwhich issof'tand w i11 shapes and sizes the basic principle notcatlse dam age to polished l mkltal. behind a lllechanical clock las not changed for aboutfivk lhundred years. Aswi th a1lneu'projects,do nottry Ofcourse m odern m aterials and tools and run before yotl can walk. Don' t have superseded som e of the oldcr startby trying to btlild a col mplicatcd ones butthis apartthe horologistwill lmechanism such asa fulI' W kstm inster still tend to work in the traditional Chilne but rather nlake som cthing fashion.C lock nlaking has long been silnplc, A m echanisll' l with a single part of the m odel engineering hobby hand isa good idea.sttch : 1piecc w'llen ratherthan being entircly thc preserN' c well polished tran look attractive as 0f the horologist and thc type of well as being fascinating to watch workshop owned by thc avtlragc wht ,n it is working. Visit l m tlsetmns m odel engincer is quite suitablc for ' w lnere (2lock nRovcm ents can be
Clock m aking appears to hold : 1 fascination al1of itsown,particularly am ongst m odt)l engineers, many deciding to makc a elok:k afterhaving m ade m odcls i At-variolls types.Tllere is something absolutcly fascinatillg about clock luaking that seel -ns to draw one towards it. This book is intcnded as a brief introduction to thc tools,m aterialsand nRethodsgenerally used and to offer all explanation of generalform sofconstruction.Itisnot a book of plans btlt those who haN' e sufficient contidence could usc ll' 1t? inforlnation it contains to l ' nakc a sinlple clock.
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A.1Ivve art' tIooking t' ( . 'rNvhen ll' lt ' tk'il' lg a clock is a l ' neans of nlakil1g a spindlk. l u/îth a hand attaohed to itrotate at11 given specd.The spindle lltpeds to tne driven by sonnt2 forl ' n oF poNs' er. usuaIly a very pri1nitiN't' : fo1 -1' 1. A I' neans to regulatc that poNs' trr is :l1s() required-i11 order tllat itvvil1rtll' l; . tt :1 Inartickllctr speed.I1-ytltlllrt' rI lollillg t() ti11ish your tirstefforts in 111s sitlk2t)1' tle Ilobby- NN' itl) êt lllastel'pitttrt' t tllttt neitller Ioost?s ()1'gCtil1s l' lltpl 'e tllêtll : . 1 secontl or tvvo :1 yu'i . t1 ' tllell ),tltl Ctrk . l prtlbêtbly gklil)g to bt' ttlisttloil' lted. 1t u'iI1 1 3k2 13( . )ssiblt ? to ac1 )itls'c tl rcasollablkl dk lgree t' lt- aceLlracy al-l d l' nork? iIllportal ltIy t() tlisctlN' tll -Il()vs'to .
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@ tl-act1ol'l tpl-lgilles. NN'lt't1-k? 1I)t?l't'.- artl
I11onc ptlrtrhases :1very'oltlclt'tlk'thtl kzlallces of it tlv' el -bk ling l vgtllated tk) kcep acculute till' ltlal 'k2getlkprally very sl mal1.lNk art?tlsu'd i1)this day and age to being ableto t nt. lq'N'tlry cheap (2Iocks allmost anysvhk lrkl tlatttre relmarkably acctlrate.Thkly are controlled by ur hat anaountsto a eolllptltcrtr1' lip and thisis hou'thataccuracy is obtaincd.These tiInepitlckls are vvhat onk? l11ight dcscribk?assotl1-1tlss-tllc). 'tlo nothavk 2 tllc lastri1atio1l ()f tllc I' lt?c11: . 111ikra1 devi(2e-althotlgh it nntlsl bt?atll ' nitted
ForttlnateIy tor tllose u'ho are begil' llling. thk? llaterial tlltt u. '1ll be used is llklilllert lxtktllsiv' e t)l'tlxpk lllsikkt wllen klolllpared to thtl eastil ' lgh;.tltcused form odelcngineering ptlrposesso do notbe frightened to l' nake a part l' nore than once ifsonaething hasgone vvrong.lt is far better than trying t() recovk lr sol mething that has not been correctly nladt l in tl ' 1c first place. Unlike btlilding I modellocol uotivcs()1-
do thkli1'1(3t 3pdrltlctIy,Tl lk?factthatï. N. 't z c: . 111)ot gtrt t1)is 1 )ig11 tlcg1 'tlk. ' l ()f ltctrtlracy does11t' bt111tli. t11t1' 1lt1otl1 *clock yN. 'i11 bc otltlagk lt .'tlsI y in:tctlrêtte and afttll 'al1 tt' ll -n)ally y' klars it Ns'as qt. lite ctlstol laary to sct:1( . 21klck to t1)k?corretrt tiI110 Ol1Ce t 2V0l-j'' WC0k ()1,SO.
cxllensivc cflstiI' lgstt'bi lbtltlgl lt.solllc bl 'êtss slletlt,a l2u'bils 111' 1(1 1)1tlct' ts of s1I&'erslek' . tIand Nve are in bus1ness. NVe aIItk. lnd to t11i11k'of cIotrks bei1g nladk 2 frol' n brass and steel btlt other nnaterials can be used.Tl' lu ' lld are a nulnber of plans availab1e tbr the constrtletion of wooden cIocks and Nvhi1e this l' nay not sound a suitablk ? lnaterials it is surprisingly robtlst.thc (. ' Jtlrnlans have used it for ycars to lllak'k ?clockscol -nnlercial1y.N ou' adays pl:!h:tit ? can be :1uscfu1l' natt ll -ial. It is t zasy to u' klrk u ilh- itis hard u'earilg and a clock I' nêtkltl of a trallsparent plastic can be a fascillatil)g tI1ing t() see.A Iso Clq' fti1ltblc arcplallsfork2Iocks l ' nad: frtll )) pllper and card. Thcy appcarto u ork N' cry svelland Iastfora Iong ti11)e.
Tools s' l()sl o1-the toklls Iikely to btll' lcetltltl u'iIlbe lbtlnd i11the ' tvorkshop of tllc average nlodelellgilldtlr.Ntlt ldle f' iIeshacksavv,Iathe,stllnc snlaIIdriIls and taps are thc basic itellls that artl wanted.In addition a slmalItiNze-sidttd broaeh is possibly the only essential .
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itell' ttlltll111igllll' It' k t1'll 'elttly be IA;tI '((41' tl' lkl ï$' k)I 'k'sllop eqtliplllel' lt. Tllel 'k 2 additit'llkllttlolsol'trtltlrsk. -tltlttiltly ttl 'c l ' 1()t absoltltely t ' tsstpltiê11. W rl aeel alltl pil' liol' lctlttcrscotl1( 1be very'tlsel tllbtlt itis qtlilklpossiblc t()g()NN' itlkluttltpll' l. Thert l arkr nAany people llllk'iI 1g N' ery line clocks ïvllt? l laN' e llever btltlgllt stl clla ctlttcr i11tllei1-1ifd.A l lellt1il ' lg tool (See (71 3:1pte1 - 6 for ftl1 -t1er
inforllatiol' l)is usefulfor layillg tltlt the Nvhklt?ls btlt oncc l nore fal' 11 -( . )111 essel ltia1. tlltzre are seq' tlraI Nvays ()f
tloil' lg tlc job Nsritllotlt stlcll :$11 itelll al ltl1ikt!ctltlel 's-Ctle eltsily il ' t,47rf. )N' ised. -A '1(. Jthe1 . tlst 2fu1 i' tt' ln4 is kllk )Ns'n 81s ; . '
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@ he nthe ' $N'ë1tcI )lllttk'ers'ltltles : . 11 -:-k' )xl ' )k?llsiN'e to btly alld êlre ot- Iitt1c tlsu- tklr (ntllt lr Ptlrposcs tllal' 1' s&'altrll Illak'illg- i1 -1' latrt thcy arc o1-doubtftll N' altlt ? Nvhkln it conncs lo l ' naking k. rIockh;. (J -cntrralIy speaking tllt . rtypc oflalhc ft'tlllklil' lthk l av' klragt' tll-l odelkpngilleklr's yvorkshop is quittrstlittlblkl.Thk ?1' nostpoptlIar()' f -all thesk. p al't ' t probabIy the N1yfo1(1 7 Scrik ls.Nvhich havc a centre hcight of 3r. ' ? i1 -1s. T 1 )otlsands ot- gootl c1ot?ks. l' lavt )bu-el' lI' nadc tlsing thcll' tand other lêtt1 )ch ( of a si1 -1 1i1a1- size and spk lc1f-icatik' l11. T1)k . l l)11!1iattlre typc ' lkttllk ?s NN'ith ccntre h:igllts ()t ' about 11: . 1lf tllat haN' c thc atls' antage k)t-being chcap and asthey art ?snaall.()bN'iously lcss spact' l is reqtlired. 5, 1ost arc ; . 1N' aiIablt ' r vN'ith :1 . boIt tln 1 ' 1)il1drill llttaurhnlk ll' lllhatl' nakt?! . itht lll' l itltraI lk n1cël tting the teeth on l. N'1eklls. lt is l' lot .
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possible to givc advickl on thtt bcst lathe for :1 nt lur col ner to ptlrchasc.il a1ldepends ( 71, 1a partictlIarprklfcrcnt)e and onc! . ibudgel.I11addition lllany t)f the foreigi1 latllt ?s tl7;lt art a stlld ' . 1rlx . only avaiIabld tbr:1 Iinlitcd period ot' tilne btlfore the spt ?cificati01' 1 is changed.Anyonc u, anting to ptlrchase a lathe Nvotlld d0 vs, ellto visitont. l(4f the I nany l uodel-engincu'ri1 )g exhibiti01 1h; 1 )k . pld throughout thc country, vN' l' 1dre it u. 'iIl be possiblu-tt) brosvse throtlgh :1 Iarge nun-1bt ' ?l' ()t' l' nachines oftlitferent l ' nakcs and typkls to ' hnd ' wrhich I' nightbtlthcnlostsuitablc. Solue of the lllethods tlskrd by clock l m akcrs a1 -t' t likely to nlak( ) a1) expcrit ' lnced engi11eer u,in(2tt. Fo1' exam ple. u'hi1e tlle cngintltll' u'ilI always try and get as nluch bearil )g surfacc for a spindle as possible.tllc elock luaker seenas to try to do the exact opposile. Holes that arc to btr used for bt zarings are dri1lt ld slllallk )r than thc dial meter of tht p spindltt tllat NvilI fit il1 tllklll-l allkl then tltlq' are realned Nvith a tapcr broach untiIa tit is lnadc. z' Ns a restllt th: spindlt' t is rtlnning on the thinnestpossiblc ring of brass. To the engineer tltl idea
stltlllds frigl ltellil ' lg btltrealIy itlllakcs t2(. )1' 1p1k zttl sel)se. . A1thotlgl) tle Illtlvtllnent or lllecllanislll is rotating col ltil' lual1y.itisl' lar(l1/. 'goil' lg t()brcak' a113,ss. r ( )l'ld spklttcll'k lkrol 'klsi1 s()t1()illg.It Ilas 10 rklalyN' t3l'k'to do il1as l ntltlllasit is ( 71 7Iy dris' illg 1tstllf and s()thklslllêtll bcarillg stll-lèlct : tl' lflstlt . ladN'êtlltage tlat it ctlts ti-ictltdl' l (. 1tlu' n to a l' ni11iIlltlll' l and i ts ël l 'u-stllt reduccs the p( 7 .vN' t ?l' I' lklt ldtll. itt'I 'tlll11)ilgs. .
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Term inology This is alltltherthing Nvhich enginct lrs l ' nay find a 1ittlk l diffictllt lo undkrrstand. A sl)11ft or spindlt l is ' klltnvn as an arbor alld the bearillg surfacc attllk' lt' llld isnot21shaftt)l'ax1k ? but a pivot.(iears bceolne svheels i11 spite of the s' ery obvious tecth alI round thelm tht)I ' naking ofNvhich istlltl l' nain partofclot-k l' naking.AIthotlgh the tccth on thc Nvhklklls are calltrd teeth,svhen they art l ()1 a pinion they ltrt p frequently describt ld as Itlavds. Thesegears(u' heels)artll -nadeol-thin section brass, Nvhich is ideal for tllc I' nckrhanisl ' n that is bcing constrtlcted in order to give :1 good tit on tllc
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H elp and A ssistance
There are : 1 considerable num bcr ot' plans available for l naking clocks of various types. Som e such as the orm aterial.To a clocklnakertlle term designs of John W ilding are sold in includes the length of brass tlsed to book form , com plete w ith full support a wheel- and fillally there is instructions' ,they are to be very highly the m echanism itselfwhich iscalled a recom m ended. Others silnilar books m ovem ent.It is a1Ivery confusing at are available as basic plans and in firstbutwe m ustrelnt lm berthatevery som e cases com plete kits can btl tradehasitownterminology.jtlstlook purchased. Thc photograph on the for exam ple at that ttsed by tht ) frollt covt!r of this book is one of a computerengineer. moN' emttntmadefrom justsuchakit,
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by Repton Cloeks and this too is an idea!way to learn thebasicsofclock construction.The British Horological lnstitute,Upton Hall,Upton,Newark Notts.N 623 5TE stock a large range ofbooksand otheritem sdealing w ith clock m aking and in addition organise courses,both residential and hom e
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im posed upon usclocksare fascinating. There are no heavy castings to hulup
aroun4 thework isnice and clean and
the end result is worthwhile.Even if afterreadingthisbookthereadershould decidethatclock making isnotforhim orher,itisstillworth while taking an basedaon the subject.Therearealso interest in them ,their history and the numberofsuppliersofclock partsand beauty of the fmish on m any, in itself booksbased throughoutthe country, canprovidean everlasting interest.
C hapter 1 - H istory Before starting on constructional heavens has becn observed for detailsofclock m aking,awordortwo thousalldsofyears and this movem ent onthehistoryofthesubjectmayassist has been applied to time-keeping readers in an tlnderstanding of time- m tlthods. The new m oon appears keeping in general.lt is not only the every thirty days and the seasons hum an race that uses tim e-keeping repeatthem selvesevery twelfth tim c it m ethods,anilnals know'when ittimkl appears w hicll fbrms the basis of the to go to sleep or,ifnocturnal,when to ycar as w e now record it. The start searching for their food. Som e cqtlinoxes w' ere wr ellknow n and tlsed plants antl trees w i)l close tlown for religiotls ptlrposes and stars and flow ers atnight and open them when sun were alm ost certainly used for daylight appears.Of course this has carly navigation,whetheracrosssea or nothing to do with clocks as we have land. come to know'them ,they are reacting to lightand dark and possibly also to Duringand priortotheStoneAge itis changing seasons. No doubt the very doubtful if anything m ore hum an ractl also started in this accurate than this would be required. fashion,sleeping during darkness and Ifthe sun wasatitshighestpointthen activeduring the daylight.The clocks it was half way through the day. in use then wcre the sun and m oon. Hum ans are ncvcr satisfied with not necessarily the m ost reliable basics and we can only speculate sourcesas forvariousreasonsthcy are when itbecam e desirable to be able to not always visible. Sueh prim itive split tim e into sm allcr parts and m ethods-while notexactly telling the exactly how it w'as donc. It seem s tim e of the day did give reasonably highly probably that a prim itive accurate m easurem entOfthe scasonsp sundialwould be the flrstbasic form of clock. Put a stick vertically in the had theiruses. ground and w hen thc shadow castby ltuus not alIleft cntirely to chance. thatstick isatitsshortestitism idday. Archaeology and ancientm anuscripts W ho knows-perhapsitwasa tree that tell tIs that the m ovem ent of thtt flrst gave som eone the idea that the
shadow of the sun could be ttsed to give :, .1 approxil mation 0ftim e. Sundials did not rem ain as sticks in the ground and we know stone colum ns werc used in early times. m etal pillars of varying shapes follow ing them .Thisisnothowevera book aboutstlndials butaboutclocks.
Thesundialsubjeetisso vastthatit could take a separate book to discuss it.W hatwe do know is that sundials were in use around 200 BC and :1 hundrcd years or so later a geared m echanicaldevice wasproduced for navigational purposcs at sca, whieh m ay orm ay notlave been a prim itive form of clock. ln 600 BC the Pope decreed that all religiotls institutions should have a sundialas a m eans of regulating tlle times for prayer so the hulnan race wasreally becom ing nlore tim c consciotls. Not alI tlle Nvorld' s poptlIation w' as (-lristian and Nvt . t1 ' :11. 1st Iook at those countrics that had not adopted the religitln to set' . -. ' kvhcrtl possiblc, ht nv tlley sorted tllingsout.Itis knoNvn that thtr (l -hincst had the idea of tlsing u. ' illcr and although therc ' svas a l1Ll1' llbi . ?l-ol-v' al -iatitlnson ll1etlltll ' llt' )-tle basic princi( 3lt . )Nvêls to tiI1a container Nsrit1)svltter.A sllaalll' lole in thebottol' l) yvotlld all()N. N' it to rtll asvay and by I' lptlklsl -lrilg tlltrttll' ltltll' ïttllatI lad gol' !t' lit N5. ' :ts possiblkl to sekl 11oïv l ' nuch tilzle 1:1( . 1 passcd i ' tll(1. if the containcr ysras I lnarked yNil1 ) glatltllltiolls- tht? tiI' l ' )e uklkllnst' tl. lcf -htlltlbe sk lel' l1ttltglance.This tylèc k)' #-clklck eN' trnttlalIy becalue used :1ll ( ' )N' e1' tlc NN. ' t)1-ld k)nd variotls
ilnprovcluents Iuade to the systeln. including ' htting a dial. ensured that the water clock rem ained in tlstl for hundreds ofyears. û-andles were also used as a m klasure of tim e.O nce itcould be established how nxuch a candle burnt down in a partictllar period of tilme. it was a sin4pIe m atter to nl:1rk the sides, show ing how lnuch tim e had elapsed sincethe candlcwaslit.King Alfred is creditcd w ith being the lirstpcrson to use candles fortimekeeping,althotlgh if he acttlally did burn the cakes the candles could not have been very rcliable. lt is still possiblc to btly candlesl marked in this w'ay' 'nowadays thcy only have novelty value. An alm ostidenticalidea to thccandle was to btIrn oiI, in a container with l ' narkings to retrllrd the til' ne that had passed as the quantity of oiI ' w as rcduccd. Forshorttim e pcriodsthklre was also the sand-glass w ith ' which many ofus w iIIbe falnilitlras an cgg tilncr.The glah;s and quantity ofsand had to be c'arefuIly lzaatelled to thc tin' le required and so the systel m Nvas generaIly used only for spkleifit2 ptlrposcs, as indicating inlennediate ti1' 1 ' 1t' lbkltsveen filIing and enaptyillg thc glass u/as notptlssiblc. W lz dtofthklreligiotlsorders thatsvt pnt t() prayer lligllt and day? Solnethillg Nvas needt ld to teI1thel ' n vvhen itNvas tiI mt lto go to the c1:1)3t)1.F.vcn thougll tht lPtlpe had dtttlrtlttd that:1llrcligiotls ilpstittltes shtltlld have a sundial. tl1is Nvasofno use af terdark orin l' nuch of the Nvklather vve havc in Britai1' 1.
various ingeniotls m easuring dt w ices that sounded alarm s were deviseds ' these included wcights on a pïece of string that was set ' lirtl to. After a periodoftim ethet lam eburntthrough the string and the weightwould drop on to a gong telling them onksthatit w as prayer tim e. The idca w as extended to include a num ber of weightsstrung to a fram e.Thestrings were ofdiflkrentlength and so burnt through atdifferenttim es.In this way thegongcouldbt tsoundedatltom atically atsetintervals. Nobody know s whon the first m echanicalclock cam e into being.by whom or how it was invented. The oldestclock known of in Europe was at Salisbury Cathedral antl is dated 1386. lt is still in working order, although no longer in the toweritcan be seen in the nave ofthe Cathedral.lt is quite an advanced clock. which incltldesam dchanism forstrikingthe hours as well as one for telling the tim e.Even this is notthe lirstknown m echanicaldevice:in 1090 StlSung m ade a device in China thatrang bells at given intervals in addition to driving autom ata although it did not have a dial for tim ekeeping. Driving autom ata was popular with clockm akersand oneearly exam pleat W ells Cathedral. and built in 1389. can stillbe seen working.Itis a very
be quite crude, m any were in fact sophisticated pieces of m aehinery. Early clocks wt prc used for ptlblic purposes and were very large. Generallythey wouldbehousedinthe towerofa ehurch orcathedral. There are records of clocks for dom estic purposes as early as l343 in France and England. The earliest surviving exam ples date from around thc fifteenth century and are of iron construction, the m echanism being scaldd down from the larger oncs in public places.A l1 these early clocks were weightdriven and exaetly what date the pendulum replaced the folio control we cannot say. However a claim is m ade thata clock was m ade w ith pendulum control in 1656. Spring drivc is hrstheard of in 1450 and thdrefore pre-dates the use ofthe pendultlm . Regular im provem ents were m ade to tim ekeeping m echanism, including in particular the invention of new m ore reliable escapem ents and in l7l5 Georgc G raham invented the deadbeat escapdm ent m aking clocks m orc reliable still.
lt is quite am azing to think that modern m echanical clocks work on exactly the sam e principle asthey did w hen George G raham invcnted his escapement.Materialshaveimprovett elaborateaffairwith knightsjotlsting with brass and steeltaking over from and a1lsorts ofotherm ovem entsatset iron, otherw ise there is little tim cs. W e do know therefore that differcnce in the basic construction of elocks have been in use for many any typc of m echanical clock. M ass hundreds of years and although the production was really the only big construction ofearly ones appcars to advancem entfrom then on,butm inor
@ ns for in)proven-1ents to bol1) cIocks Ct11(1 M any people buy nltlchanislthese quartz clocksand l' nake cascsof Nvatchescolltillued. various types to housc thel -n: it is a In the twentieth century, clocks alltl hobby on its own in which large watches have sklen advancem ents that numbersofpeoplearchappy to indulge. would nothavebeeltthoughtpossiblc. cven atthe startofthe century.A bout Betbre ' linishing Nvith the history of sjxty years or so ago people hrst clocks it is interesting to think how started to experim cnl with the ustlof tinle itself has changed. Until quite electric clocks. t-'ertainly thcy u' crut late in the ninetecnth century ey' ery vcry prim itive in comparison w ith town or district kttpt its own time. whatwas to com e later,butthey had Com m unication between areas was the advantagc that it was possiblc to very poor,w ith Iim ited transport and synchronisc several clocks togcthcr itm attered notwllattim c it was in a which was idealin a factory orsim ilar tow n forty or lifïy m iles aw ay.W ith ( . ,slabIishm t )nt wherc m any people the com ing of the raiIw ays al1 this werc elnployed and a!I wouId be changed.A person travelIing frol n say starting and stoppillg work atthe sal ukl London to B irm ingham and then tim e.Priorto thata bcllorhooterw as wanting to get a connection to used' , a system that in may placcs som cwhdre else netlded to know what Iltstcd tlntiIquitc rccenttim es, tim e that connection would leave in In-lprovcl m ents in thc Iuanufacturc of relation to the train on which he orshe elttctric clocks were rapid unti1 Nve would arrive.The railways thcrefore reach the stagc at u/hich svt? are at organised their ow n time, known as today where it is possiblc to buy a Railway Tim e, which was consistent clock w ith :1 digita .I rcadotlt so that right throughout the country. Ilobody trvtln needs to know how to Gradually thiswasadopted throughout teI1 thkl tim e anym ore. The m odern thc country until evcryone used the eleclronic m astcrpicccs can keep saluc.N ow tim e is relatcd directly to perfbcttim : and are farm ore accurate thkl firccnw ich M eridian,and know n than any except the m ost expensive as Grcenwich M ean Tim e. Othdr m echanicalclock. Probably because countricsalso take theirtim e frol' n the ot -thcirefficicncy they do nothavethe m eridian w ith allowances m ade for faseination ofm echanicalones,which tim e zones.A sresultitis possiblc for art l stiII m ade today 170th anyone,anywhere to know whattim e eom mercially and by alnateurs. itis in any othcrpartofthe world.
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C hapter 2 - T he F ram e The fram e ofaclock willgenerally be
The nexttask is to m ark thd position
made of two flat plates. joined ()f the pillars which join the plates together, at or near the corners with pillars.Al1 parts are tlsually m ade of brass except in exceptional cases wherewe m ightguta steelfranle fitted with bushes.The plates are sawn and filed to sizeand afterensuringlhey are flat and square they should bc hcld firm ly togetller w ith clalups. preferably thc toolm akers'type urlile two or three sm al1 holes are driIled through som dwhdre ltlar tlltlcorners. These holtlsarutto actzdptpinsorrivets that are tlsttd to cnsurd tlle plates tlt) not separate during operatio1sm ' onct! the pins and rivots are i11 plactr thkl ( 2lal mps can be rel moved.
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together and drillthe holes forthcl -n; wt lw illcol -ne to how they can btlfitted shortly.OccasionalIy clock designsdo not have this type of plates instead they arc m adc Nvith strips of brass. lmort) otztcn lhan not ctlt into fancy shapesand instead offourpi1larstlleri a are only tuo- one al catrh tlnd.The
principleofjoiningthelzntogetherand drilIing thtl piII: 11 ' holt' ts renlains cxact1y t1k l sa1' ne. . A. s 1 3tli!ding . Progrklsscs011diffcrencesyviIIelutplgt' !for k lx:1lup1( . , thcre NviII 1' 1ot bkr a pendtllul' ) l alltl so they Nvill not be fitted svith a back cock.
@ T he Pillars GencralIy speaking the piIlars or spacersas the laym an woultlcallthem w illconsigtofbrassbarsand they m ay or m ay not be shaped.Shaping is a m atter ftl1-the individualbuilderand in alim ited way istheopportunity for him or her to express hiln/hcrself. Fitting thc pillars to the fram c isdone in severalways:son' ld are hoIIow and a stud ispushed rightthrough and the parts held secure w ith a nute or perhaps the cnds of the pillars nlachined dou'n and threadcd to akleept a nut. ln othe1-k' laskls they are drilled and tapped and screws passed through the fram es.into them .A third alternative,isto l ' nachine a step in the pi1Iar cnds and pass this tllrough tht l holes in the fralnes, vs' hich arc thell seeurcd ' w ith a taper pin, htted in 11 holedrilled acrossthe step.Onething
thatis conllllon to alIlnethods is that when asselnbled the fralmes m ust be rigid and square.
Setting O utT he Train
M arking O ut
The m ost Comm on way Of setting out the train is to scribe a straight line lengthways dow n the plates and to set the escapement,centre or hour wheel and the great wheeland barrel along this.Thethirdwhcclhasto be setatone side in orderto allow the pinions and wheels to mesh.Just occasionally we com e across another dcsign w here the escapementand hourwheelarein Iine and both the third wheeland barreloff set.This is very rarc and any details requiredforsuchanarrangem entwould be available tiom the drawing and ally instructionslhatm ightgo along with it.
Som etim os clock plans w ill give m easurem ents showing where pivot holesw i11beplaced' ,ifnotitwillbe I ' ICCCSSCtI' Y to Wrrk Otlt Spacings for oneself.Startby lightly dotpunching a suitablc place forthe greatwheelon the centrc line.Use a depthing toolto mark out position on the line of thc m inutc wheel' ,thîsm eans meshing the great wheel pinion w ith the m inute wheelso they run very sm oothly and w ithout any binding.W hen satisfsed
with themcshingsusethetoolto make :1 seeond m ark on the linc that has becn m arked on the plate.
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Depthing Tool
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A depthing tool is sonacthing that solne people Nvill nt't has' e eoll'e across before: it is a tool for setting out gears to ensure that they run sm oothly.They can be boughtbut for norm alpurposesa homc-m ade duw ice
willdo jtlst as well,those that are Purchased being far m ore sophisticated than necessary for oceasional elockl n aking ptlrposcs. Thetoolissil m ply a nneansofmeshing whecls and pinionssor two wheels or the escape w' heeland pallets.st athata check can be nlade to ensure tlcy rtln properly.A professionally-madc tool w iIl be spril1g Ioaded and fuIly
adjtlstable.but good rcsults can btp obtained fro1,t : 1 sim ple dcvict!
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swiveltogcther and with lnJ()holes to acccpt puncheh ;.The ptlntrlles artl the sal ue diam eterasthe whet!larborsand so the wheel and pinion are simply
slipped on and adjusted.Ifdiffercnt sized arborsare likely to btlusedafit brass bushes that can be intcrchangeablc.Oncofthepunchesisset in the nlark already m ade and the other is lined up on the line on the plate. A slighl tap Nvith a snnalI ham mer and thtlcorrectplace for the arbor of the hotlr Nvhcel is lmarked, John W-ilding,who isone ofthe tinest (21ock lmakers i1, 1 the country rt lcolllllltllldsa piece ofslottkld bar for the saluttpurpose:an idea thatworks very wel1.
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Tl 'e tool is ntnv used to sct t11e distance of the third whecl- w hich tlannotbe sited 01' 1the line betrause it would then be ilnpossible ttA nlesh al) the whecls properly. There is no specific angle atwhicl)to sctthe lhird wheeland this,pltlsw hetheritshould be setto the rightorIeftofthkl1ine,is am atterofindi vidtlaltaste.Gencrally speaking an angle ofaboutforty-five dcgrees is used' . w hatever happens
istlsed.The l' nark should be l madeol) the Iine used by tht? great wlleelalld lminut: whce! and that is the clock train lmarked out.Holcsforthc pivots can be drilleda but don'tforget they should be drilled tlndersize.svllellthe platcs are separated they can be opened outwith ataperreanlerso thtly area nice running tituzitlatle pivtAts.
re is stiII ond m ore opdration naakeanoteoftheanglejustincaseit The r eqt lired inordertom akea11the pivot needs to be rcferred to later.Having holes, for the pa1lets of the escapem ent also need to be set.The pallets and the escape wheel are m ounted in tht, dcpthing tool and
decided where thcwheelw illbe going repeatthc operation with the depthing tool so that a nlark is nlade for thc third ' vvheelpivotll0lt).From there thk l tool is used to 1ay out thc distancc fron' l the third whttt )l to the escape
adjusteduntiltheyworkslnoothly in the sam e way as before.
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The plates are now com plt zle cxcept thatifthe clock isto use a pendultlllla back cock lnust be fitlt ld.This is a bracket that stl pports the suspttnsion jbr the pendultlm , w 1 lich can bc fabricated orm illedfrom ago1idblock ofbrass.Ittakesthd tbl-j n ofabridge to clear the palletarbor.the pivot of which locatesin 11hole in the cock,the suspension being ïitted on ti ' le arbor between the plateand the bearillg, Itis essentialfor the gootl runnilg of the clock thatthecock issecured hrm ly to theplateand w illnotwork loose.Itis also essl -ntialthat the escape whccl arbor when fitted to the coek is at ninety degreesto the plates.
to l' nake an attractive pattcrn and tl)is is a nzatter of individual taste. Thc fretting wi11obviously need to bu-donc Nvith the platesseeured together. One way ofdoingthisistodraw asuitable pattern on paper,taking care to avoid allpi vot holes,cut out the pattern, stick iton the plates and cutround it. Do nottry and chain drillbutdriIla couple ofholcs in strattlgic places and use a piercing saw or a poweroperated scrollsaw ifone isavailable,
tocomplet:thejob.Finally cleanthe edges ofthe cutsusing sm allfsles.
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C hapter 3 P roviding T he P ow er M ost people when starting clock m aking, begin with a weight as the Power source and so we willIook at how thisisdone lirstofall.A suitable barrel is required roulld which a line can be wound.This in turn istied to a weight, but not directly because the weightisconnectcdto: 1pulley andthe drive line passes through the pulley and is anchored on orncar the clock. The usualplace is one ofthe pillars. Any tubing wiII do for the barrel. although it m ust be thick walled.
G enerally speaking brass is preferred, m ainly because of its non-rusting properties,btltthere isno reason why it should not be of stecl: many years ago m ost clocks were m ade of iron, although theuse ofthatm aterialisnot to be encouraged tlnless trying to build a rcplica.A spindle,or arbor as horologists prcferto callit,is passed through thc lniddle and on one end of the arbor isltsquare.This isto accept a key u'ith which to rewind thc line when itreaches a 1ow point.
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T he Barrel
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One end of tllc barrelis plain-other than fora hole through which the gut is secured. The other end form s a ratchetreferred to as the click wheel: this can either be m ade integralw ith the barrel or fitted perm anently in place to an end cap.How the end caps are fitted is a m atter of personal choice,butthere ism uch to be said for using slnall screw s to hold them in position as it enables it to be dism antled should any work be needed on the arbon Also conneeted to the arboris a whcelorgear.ifyotl prefer, callcd the great wheel. This connects via a pinion to the train antl the ratchet prdvents the barrel from unwinding,exceptwhen controlled by the restofthe clock.To Iocate in the ratehet is a specially shaped m etal plate known asa click and a spring to hold itin position.Although the barrcl can be left plain it is a good idca to m ake a continuous groove in it to allow the gtlt to wind on and off evenly' . rather than pile up.A sm all
off tool is idealand ordinary screwcutting m ethods call be adopted.The depth ofthe groove shotlld abouthalf thc diam eterofthe gtltbeing used and about seventeen or eighteen turns are required.Therefore ifthe barreliszins long the lathe needs to btl sd to cut nine threads per inch, or the ncarest availablefigureabovethat.
@ and to m ake the ratchet sm oother in use.The m ore normaltype ofratchet will have about tllirty-six or so teeth and cutting by lmachine is alm ost essential.This is not to say that the work cannot be done by handm buta high degreeofskillisrequired to get aIltheteeth tothesamcproGle,notto m cntion thatthe task w ill take som e considerable tim e.
The G reatW heel Thc grcat wheelis mounted on the barrelarborand drives the train via a pinionandapartfrom cuttingtheteeth itisquitestraightfonvard. Astheweight unw inds,it drivesthe greatwhecland when the clock isbeing wound up the ratchetallow sitto slip past.
T he R atchet The ratchet can again be of steclor brass although brass is generally recomm ended and the teeth are cut in the same way ason aI1the wheels.The ntlmber of teeth varies considerablydepending on the design ofthe clock. l11 som e instances designers havc deliberately kept tbe number of teeth on the ratchet to the m inilnum .This allow sitto be filed to shape,avoiding the necessity to m ake or btly a specially-shaped ctltter. In these instances the teeth are curved in a gentle radius,both to facilitate filing
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This isthd nam e given to thepawlthat locates on the ratchet and prevents it unw inding.Itisusually liled to shape and the shape isnotdifhcultto m akeq the only critical part being thc distance bctween the hole centre and the tip ofthe blade.Itshould be made
Thttspring holdsthe clickdown onthe ratchet wheel alld m ust therefore be strong enotlgh ttA do so. while atthe same tim e notbcing so pow erfulasto drag and causc morc power to be needcd than would otherwise have been so.Thespringsvary considerably from gauge plate and hardenett then in length and shape and so materials tem perdd to a dark blue colour.As an lllay vary w ith differcntsprings.M ild alternative itcould be m ade from luild steclcan be used tbrm ostsprings and steeland case llardened and while not although itm ay sountla m ostunlikcly giving quite as good a result as tlle m aterial. ham mering thin scctions prcvious m cthod a Iong lasting and causcs a work-hardening effect, reliable click would stillbe the result. resulting in springiness. Anothpr '
Screw passes through GreatW heel .into click! y//
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usefuk material that has a sim ilar effeet is drawn phosphor bronze, a m aterialwith a naturalspring to itand which isalso very easy to work. Like a1l parts for clocks suitable springs can b: purchasetl eom pleletl and ready foruse ifone wishes-
The Pulley The weightthatwilldrive the cloek is suspended from thedrum viaapulley, which effcctively halves the weight 27
@ (;enerally the barrel wilI differ
@ applied.There is not:1grcatdealcan be saitlaboutpulley construction'wut are aI1 fam iliar with thutshape ofthe wheel w hich should generally be of brass and run on a steel axle.The fram eofthe pulley can bem ade from a piece ofbrassplate and thatis:111 therereallyistoit.A ppearaneecan btl im proved by drilling holes in the pulley wheel.
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Various m aterials 111-: used asweights which arc also made in a variety of shapes.A nicely polished length of brasstubefilled with lead isideal;do rem eluberthata hook isrequired with which to hang the weighton thc cord and thatthis m ustbe setcentrally to the diameterso thatthe weighthangs straightand docsnotlean atan angle. A lthotlgh the weight is nzentioned in this chapter.beeause itispartofthe driving m echanism , itw illbe one of the last item s required.lt is obvious thatwe cannothang any old weighton the clock and cxpectitto keep time.It 1131. 1st be sufhcient to kecp thc clock going withoutcausing itto work attoo fasta rateand so thc am ountofweight required will be for experim ent.
A good idea isto gcta used food can and fitto itsom om eansofattaching it to the line from the drum ,fill tlle tin with pieces of lcad or other heavy material and run the clock. Keep rem oving sm all amounts until the clockstops.Thishastobedoneovera period of severaldays.W hen it has
stoppe; weighthe contentsofthetin, add about half again and m ake the nnished weightto this m easurem ent.
Spring D rive So farwt?have dcaltonly with clocks that are weight driven,which m eans they are either fittcd in a long case or hang on a wall.W hat ifwe want our clock to sit on a shelf? It is hardly practicalto drilla hole in the shelfand run a cord through that to a wcight. The answeristo drive the clock w ith a spring:som ething with which we are al1 fam iliar and springs are freely available. They arrive coiled and sealed tightly with a fastening alm ost ready for use and litinside the barrel using two hooks, one of which attaches to a point inside the barrel, the otherto the arbor. Greatcare m ust be taken when dealing w ith springsas
theycancausenasty injuriesanditis advisable to wear heavy gardeningtype gloves and m ost definitely to wear protection for the eyes.Special devices are available for setting Springs in barrels and. while it is
possibleto do so by hantt ifin doubt find yournearestclockm akerand take thelotalongthere,wherea specialdevice Willbe available which will enable the
jobtobedoneinamatterofminutes.
considerabl y from that described fbr thc wcight-drivcn clock.Fora startit becomesobviousthatoneend mustbe removable in orderthatthe spring can
beinsertedbutothermajordifTerences also occur.A lthough notunknown for a clock to be driven directly by a spring, particularly if one buys a cheap one, it is m ost certainly not good praetice.W hile the weightdrops at a given speed throughoutits lcngth the spring behaves vcry differently. W hen tightly coiled it creates considerably m orepowerthatwhen it is only partly wound. W atch a clockwork-driven toy and see how it slows down w hen the spring starts to run down and of course that is som ething that is not wanted in a clock.
The Fusee To avoid this problcm it is usual to connect the spring, via a device known as a fusee,w hich is a tapered and grooved Iength of brass on an arbor,on which issetthe greatwheel. M uch the sam e way as the situation w ith the barrel on a weight-driven clock.A cord is wrapped round the grooves in the barreland runs to the fusec.W hen the spring is fully wound the chord passes round the sm allest partofthe fusce,effectively acting as a brake.A s the spring loses its power so the chord winds to a larger diametcr keeping the rotation of the fusee at an even speed.The arbor on which the fusee runsis sim ilar to that 29
@ ofmostpeople.Takealength ofbrass
of the barrel on the weight-driven clock and the barrel now works independently oftheclock m ovem ent, providing the powerand nothing else. The clock iswound via asquare on the fusee arbor,which in turn rotates the barrel.A sthe spring is hooked inside that,ittightensup,to be released ata
bar of a slightly largerdiam eterthan the maxim um diam eter of the fusee,
putitinthethree-jaw chucksfacethe
endand drilla hole through itslength for the arbor. M achine the outside diameter to size and we can now guaranteethatthe hole forthe arboris regularspee4 with thefuseeaeting as true to the outside diam eter.Set the a continuous gear and compensating top slide over and m achine the for the unequaltorque of the spring. required angle, then use either a To enable the fusee to be wound the radiusing tool or a hand graver to conical-shaped part is not directly generate the required curve, which attached to the greatwheelbutdrfves m ustbe sm ooth. it through a ratchet as already So farithas al1been easy going but described forthebarrel.From therethe now we come to the only tricky part, poweristmnsm ittedtotherestofthetain. which is to m achine the continuous groove. A set-up for coarse screw cutting willtake care of the spacing Fusee C onstruction w hich isthe sam e asthatforbarrel,so M any peoplefightshy ofm aking the al1we need is to organisc a toolthat fusee and preferto purchase it,butit can be adjusted in depth as the is a task thatis wellwithin the ability carriage m oves along.This too is not
@ setatitslowestpossiblespced forthe
djm cult:m akeupapieceofsteelw ith jbur pins stted in it as shown in the drawing and clam p itin the toolpost Parallel to the lathe axis and f5t a suitably radiused toolin the end of a square bar that slides nicely through the gap. Either fit a handle to the opposite end or w rap a quantity of insulating tape or sim ilar m aterial
operation, in back gear if possible. Bettersti11tlst n:1handle in lhc m andrel and rotatethelatheby hand. Although it is suggested above that the toolbe madefrom squarebar, thisispurely to preventitfrom rotating. Readersw ith sutficient confidence in their own ability can usea round one. The tool round itto avoid injury.(Do notuse m ustrem ain atornearthe sam e angle loose material:itm ustbe held srnaly throughout operations to be on the tool w ith no danger of it successful. The operation is not
coming offè) It is now possible to diflicultandthereisa1otofcnjoyment apply gentle hand pressure to the tool protruding throughthetoolpostasthe carriage m twes along alld in thisw'ay to m ake the required grooves. If the first cut is not deep enough the operation iseasilyrepeatedbypicking up the groovew ith thetool,betbre the Iathestartsto rotate.The Iathem ustbe
to be gained from the tkeling of having created a nicely-shaped ftlsee. lt is probable that the grooves will have a rough finish on them so cut a piece ofdowelto a shape thatwilIfit them and using Brasso or similar polishing m ateriatand w ith the lathe running underpowerand in back gear
Distancebetw een pillars an exâctfitforwidtb of toolbeing used Clam p this end in toolpost
W 31
@ studdillg is notavailable it nlay be
run tllt-dovvutli: ll( )llg the groove ul ltila sluoolh finish is obtaincd.Finally part tl' le vvork 0ff t)r if it is thoughtto be too large to be parted off,saw itoff.lf saw n,lllotlntilon a l' nandrclbdween centres,tlsillg a half centr: attl3c end thatissawnswhich can then be faced to size.A suitable hand-ttlrning rest for using a hand graver to get the curvc and a self-releasing handlc to tit the nnandrelare described in the book KUseful ' W orkshop Tools' ' which is nul mber 3l in the ' W orkshop Practice Series.
Untbrtunately lhklabovemethodsonly apply'w' hen a lathe has suitable screw cutting facilitiesand this is notalways so.Generallyil' wouldbeadvisablefor those w ithotlt these facilitics to purcllase a fusec ready m adc.Son' l: pcopltdonotlikctobuy suchiten' lsas they like the feeling of having nladd every part for thenlselves. For thosd people, lt is possible w ith a little
possiblt) to oblain a Iarge dianleter bolt' . 21 l' netal scrap yard is a good plac:to searcl)forsol nething suitable. Tht lothercnd ofthisnlustbe centred and stlpportedby tlletai1stock.Take a llut that fits the thread and silver soIder.or i1 sol' ne other fashion fit a shortlength ofmild steelbarto it.Ifit is Iarge enotlgll perhaps a couple of sm alIscrdwsurould do the J 'ob.Use a piece of bar at rightangleg to this to connectto thd screw-cutting tool,via a slotin the firstpicce.W henthe lathe is rotated the toolw illnow m ovc along the thread and w ith the toolin contact with the fusee the continuous grotwe wi1)be m ade. M ostpeople with the snaalllalheslhataretlleoneslikely to lack seresv-ctltting facilities, are tlnlikely to be luak'ing a clock which would reqtlire 8 , Iarge dialnete' r fusee and the above m ethod w'illthereford vvork quite NveII.
Contintling from the power supply towards the dscapement are a pair of wheelsand pinionsdesignated asthc third and hourwheels.They form thc just to beatthe oddsand do these m ain partofthetrain ofwheelsknow n thingstbrthennselves. asthe gofng train which eonnects the Thc fusee willhave to be hnished as power unit.whether it is a drum and 1 spring and fusce, to the far as shaping and driIling is weight or : e s e ape m e nt .svhen firstlooking into a eoncerned. M ake a suitable w ellcl oc k i t a ppc ars to be a iungle of fitting m andre1butfittheendthatwiI1 whee l s and pi nions and it is this go in the tailstock centrew ith a length a ppa r c nt di s or der thatfreqtlently puts ofstudding wilh acoarsethread.This P C t op I e o f f m a k i 1g or repairing a thread w i1I tlltim ately bc the one cl ock. W hi l e t hes e gears and pinions transferred to the fusee so itw illneed to have a Iarge diam eter, in order to m ay be in a num ber ofeom binations, ' ne for get a sufficiently coarse pitch. if the actual tbrm ation is the sal
virtually eNr ery cltnck,The greatw'heel dfivcs a pinion,which in turn drivcs the centrc wheel' .tllc pinion connected to thatgocs to tlltlthird wheeland the Pinion for thatis in turn connected to the escape wheel.
on tl' le salllt ' t:1rbol -astllklcentrc svlleeI. Thc centre wheelhas sixty-four teelh and as ifcarrics11)e Ininute hand 11:1st rotate once an hour. This in turn connects' with an eigbt-leafpinion on third wheel arbor, w'llich has sixty Basically therefore we have four teeth.Itconnects to anothereight-leaf pinion on the cscape wheel. ' W hen wheelsand three pinions,which is a designing 1 train itisessentialthatthe nice easy m anageable num ber, Partictllarly for anyone versed in escape wheel shall m akc sixty ons (seconds) for each one engineering m atters. Various revoluti r e vt a l ut i on of the centre wheel colnbinations of wheels are tlsed but ( mi nut es ). To check this multiply there m ust be a logicalsequence.Let t oge t her t henum berofa11theteeth in us start w ith a hypothetical clock, t he dr i vi ng wheels and divide the althougb the train used will be one a ns we r by t he num bersofleavesin the thatis quite com lllon. pinions,lmultiplied together.W ith the The great wheel connected to the exam ple lhat bas becn used the drum arbor has ninety-six teeth and tkm mula in tht! appentlix gives all the w illconnectw ith an eight-leafpinion detailsrequiredto seehow itworksout.
ingenttity to put on a continuous threakl in these circul mstances if sttfficiently detcrlninedo or perhaps
32
.1I '..kudkki
V
@
@
C hapter 4 - P endulum s A pendulum is described as a heavy tim ed by using his pulse. The particle,suspended from afixed point im portant thing about it was thatthe by a fine inextensible m assless rigid oscillations were isochronous which threa4 so thatitisfreeto oscillateon m eans sim ply that the tim e for one a verticalplane.Galileo the fam ous complete oscillation was always the astronom er is credited with sam e.His son iscredited with the frst discoveringitand legend hasitthathe use ofthe pendulum and whateverthe was watching the m ovem ent of a truth of the story it has stood swinging lamp in church which he horologists in good stead ever since. '
<.... .ng Suppor Sprl t ' : ' '. Block ------ /z Rivetor Screw
BackCcck --.. -' stlspensicn - '--Spring
@
P
Back Plate
1'4
..a
Pendulum Rod
:: 2)..4. ::,': : ; .: 1:.: . .:: :.,:
:J ;: !..' . ... . :*:.. : : ). . ,...
., ,.
1... : ,: .
.. : : **
'
Make up t? fpendulum . assembl v, xyou, ' l. ng N . uu b pensionspring and methodofadjustment.
v .
-
..
t v NwRatjng Nu x
Pendulum Bob -' .-
-u ...
ulum Rod. square whereIt passesthrough bok).
Ratl .ng Screw 35
.
I.iIA
!
@
I
Although a pendulum appearsto move backwards antl forwards it actually takes a sinusoidal l ' notion, a m ovem entthatis not quite a circular one, but w hich for all praetical purposes we can consider as an ordinary backwards and forwards m ovem ent. This is controlled by gravity and as a result the distance from the train to the bob varies according towherethependulum isin use.There is a also a variation in gravitational pull, depending on the height above sea level. Tl4e latter is
Togetherw ith the escapemtlntand via the suspcnsion and crutch the pendulum is rcsponsible fol m aintaining tim e, using Galileo's discovery that each oscillation takes the samc pcriod of tim e. A sim ple pendulum consistsofthree parts;the rod, the bob and a rating nut, a1l requiring carefulattention iftbeclock is to function properly and is to be accurate.The num ber of tim es the pendulum vibratesorsw ingsdepends on itslength and isselected according to thetypeofcloek being m ade g such thatadjustments can easily be case and wallclocksm ore often. Lon than m adeto takceareofthevariation. notw illhaveapendulum thatvibrates once per second, 'sm allerclocks w ill have correspondingly shortcr pendulum s and will vibrate faster. Q A A
@ This m eans that the length of the Suspension Pendulum is also in directrelation to The suspension consistsofatlatspring the clock train: a pendulum that t hat is strengthened at the ends with vibrates every second will need met al blocks allowing one end to be differenttrainto ahalf-second one. supported by the back cock and the otherto connectto the pendulum. The spring must not be too long or too strong and atthe sam e tim e itm ustnot be too weak either.M ost designs will give intbrmation on the correctsizc of spring to be used:ifnotitw illhave to be a m atter of trial and error. Fortunately there is a rcasonable am ount of latitude available in spring selection btlt if in doubt it is worth considering the purchase of a readym ade unit frol' n a supplier, having in m ind that unless the spring selection and m ake-up isrightthe clock w illnot ftlnction prtlperly.The back cock also needs to bk l m ade and assembled ' carcfully as,ifitisoutofalignm ent,the pendultlm cannot function properly.lt mustalso bemadewith suflieientstrenjp rth to give good stlpportto the set-up.
The R od
(1O l The t7r/.//c. /7is theJplrf thatf.qtnoved /)j.'the
b' v' ing t?/'the./' pt/?7pl ,k/zfzn. It./i' lx on the tçtwrt ?
Relatiollshi p r? /' /pt,?;t/l//l/?A?toc.q'tqw/.?t.?nlovenjf?nt 36
.. ..L i1
arbol) tht,prongs f' aa eilht??-side ft' ?(?tr//?kg ' '/thepEa/llf/?, fp?suspension spring. t/gtzln.$
The rod must be straight and have 21 stlitable m eansofconnecting itto thc suspension tlnit at one end.The end thatfitsthrough thklbob isthreaded to accept the rating nut. Depending on thtltype ofbob itmay be necessary to m ake the end square so that the bob cannot tw ist outof line.Selection of m aterialfortherod isimportant.lthas already been stressed that for correct operation the weightofthe pendulum
@ thatisused.A m orem odern material
mustbe concentrated in the bob and if a heavy rod isem ployed this wil!take the weightaway from thatarea.There is also a slight problem ofexpansion and contraction of the rod w ith tem perature changes. M any ideas have been introduccd to com pensate for this: som e simple, others very complicated.W hetherornotthe home constructor will want to go to the effort of m aking a com pensating version is a m atter for individual choice. Doing so involves considerably m ore work than m aking a simple one but no doubt could in
is Invar which although expensive may not be prohibitively so and has the advantages ofbeing light,easy to
workwithandnotsubjecttochanges oftem perature.
The end ofthe rod has to be threaded to acceptthe rating nut,which allows
adjustment of the height of the
regulator.lf a round ortubular bob is being used then the rod can be Ieft round where itpasses through' ,ifone of the flat type is used then the rod w ill have to have a square on it to preventthe bob from tw isting in use. itselfbeaninterestingproject. Ensurethatthe square ispositioned in Assuming that at this stage anyway, such a way thatthe bob willrem ain hen swinging. readersare going to be contentw ith a parallelw ith thctrain w' single rod then the materialchosen for lf allowed to twist at an angle the it is worth consideration.W hile brass balanceofthependulum willbc upset. looks nice it is also the m etal that suffers m ost from tem perature chal zgesand so ifitused f' brreasonsof The Bob appearance the rod shotlld be as thin Although we tend to think ofbobsas as possible or alternatively usc thinbeing m ade either in a lens shape or walled tubing.Alum inium tubing is rountt in fact.many clocksusedquite also a useful m aterial and has the fancy shapes, in particular French advantageofbeing lightand allowing clocks were adorned in this way.but the weight to be concentrated in the of course m any French clocks were bob.W ooden rods have the advantage noted for their ornate appearance that the m aterial is less likely to anyway.ln generalthehom eworkeris expand or contract with clim atic going to use one of the two standard conditions and on a long case clock a types and so it is these we will piece of dow el can m ake a very
effective rott asitisalso lightweight. Itshould be wellsealed w ith varnish or sim ilar m edium to prevent the absorption of moisture from the atm osphere. M ake certain that the dowelis perfectly straight in the first place.as indced m ustbe any matcrial 38
@
conccntrate on.
For small clocks and probably wallm ounted ones as well the standard lens-shaped bob is usual and not diflicultto m ake.Startby m achining a hollow in a piece ofhard wood;m ake sure the m achined surface is perfectly
smooth.Cutout two disks k)f brass kt little largerthatthc outside dianletcr oftheproposed bob and allnealtlcnh, if necessary re-nlarking the circltls afterannealing. A good alternative to brass is giltling lmaalwhich is l' nuch m ore ductiIe and needs less annealillg than norlual brass shcet. U sing êt wooden bossinglmallctsshapcthetwt) disksby gcntly ham m crillg them into the hollow sin the block. As soon as thebrassstartstowork-hardcn. anneal them again antl kccp doing so whenevernecessary'- do notunderany eircum stances try and w' ork the l' netal if it hardens. Dtlring tlle shapillg operations take care thattle work is kept centl-alto the ciretlluferenee of
thc 1,k)lI( )wrs.ltis alItoo easy to have the Nvork slide to one side during the hoI1ou' ing-otlt process and in ' which case the bob ï. viIIbe ofno use atall. Periodically put the tu' o ))ieces together to check the ' ht- until the k ldges naeet alI thc u'ay roulèd. Each ' piece ntlcds a snnall section ' I iled out fortherod und and atthisstage littlc lmore than a 1ick yvi1l do. W 'lpk?n satisfied w ith the ho11ou'illg-otlt proccsss drill a holc about 5. .1(' lins dianzeter in the celltrtl of ontl of tlle piecesand deburrthe ilolcs. Clean the pieces tlp by soak'ing thel' n i1 a soluti()n of citric acid: two tablespoons to a bucket of water is 39
I.1 .du.
.
@
@ aboutright.Tllt ?y need to stxlk in itfor a couple ofhours orso to cnsure they ark)clean entAugllto be silversoldered together. M ake up a soltltion of flux by m ixing il w ith m ethylated spirits into a sm ooth paste and sprcad it round the inside edges ofeach piece. putthe two pieces together,with the Piece w ith 11hole in iton top,making sure the edgesm eetand thatnicksthat have been filed otltare levelwitlleach other.Lay the assem bly on a brick and puta weighton top so the picces will retain theirposition.W hellcompletely satislied that thc parts art l located
.. ..1 *
correctly heat then) up and apply siIversolderabotlttllreeorfourplakres round 1htledges.f'oolittlffand put il back in thcacid to elean it.
W'ith a needle filea open the places u'here the nicks have been made and file a square tbrthe pendulum rod to go tlzrough. The top hole can bc opened with a taperream erto obtain a round hole. M achinc a Iength ofbrass tubing so thatit is a push lit in the 5/l6ills diameter hole. Nlake up a shortlength ofrod the salnediamd er asthatused forthependulum andw ith
a square on it that is also the sam e. Paintthis.using eithercmulsion paint or by using the white Puid w' hich typists use for corrcetion purposes. W hen dryopush itintothebob-fitthe tubing into the hole and then heat som eleadtom cltingpointandpourit through thetubeuntilthebob isfull.lt w illspi11outoftheedgesbtltthisisof nO COIISCQIJOFICC aSally StlrplusCan be cleaned off later,Solder a disk in the
%...'k '(.
'dianleterhole in place ofthe tubc. Finally use a fine file.tm ttry paperor cloth and any other abrasive material thatm ightbe a personalfavourite,to tidy the surfaeesofthe bob and m ake itlook presentable. .
R ound Bobs Round bobsatfirstglance seem to be far casier to m ake than the lens type
@ fills al1the space.A good alternative
and in som e waysthey are:,thisdoes notm ean thatcare need notbe taken jnthefrm anufacture.Thefinishthatis required hasconsiderable bearing on how they arem ade.Forexam ple some People are contentto drilla piece of castiron barand usethat,whichwhen cleaned and painted can look quite good while atthe sam e tim e itisthe m inimum oftrouble to m ake.The only thing that needs particular care and attention is to ensure that the hole drilled should be a nice fit for the thread for the rating nut.The same principle could be applied using a length ofbrassrodandthiswouldgive a betterappearance butlessweight.
A more com mon way isto use a piece ofbrass tubeand afterensuring both ends are perfectly square, start by silversoldering a piece ofplateto one end.Thisisthentrim m ed totheedges ofthe tube to give a niceneatfinish with ahole drilled centrally in it.The screw for the rating nut will be travelling through a piece of brass t' ubeEtted insidethebob and thehole should be a close fitforthatto slide into.M ake up a length ofm ild steel barwith a step to ' lètthe inside ofthe otherendofthetubeandaholedrilled centrally in it to accept the central tube,referredtoabove. M ake sure that thistubeisexactly centralwhenfittedo Othenvise the bob willbe offcentre and this w ill intertkre with the Operation of the pendulum .Fill the Outertubewith lead.lfnecessary heat the base to ensure that the m aterial
to lead is one ofthe low -m elting point alloys sold for casting in rubber m oulds. These also have the advantagethatthey arenottoxic in the sam e way thatlead can be.Depending on theamountofweightrequiredothe tube does nothave to be filled to the verytop,butm akesurethattheslling m aterialfills thearea com pletely and there are no air pockets that could throw the bob off balance.The fnal aet is to rem ove the steelspaeer and puta brassplate overthe top:thiscan be soft soldered in position. A lternativelyabrassend canbem ade w ith a lip so thatitisa push-fitin the tube.This allow s m ore w eight to be added ifrequired. A merican and French clocksoften use a fancy shaped bob and these are usually east' .they ean be bought.To m ake thcm oneself requires either a high degree of skill in beating sheet m etal to shape or the ability to m ake suitable patterns to have the shells cast.Any casting would be bestdone using thelostwax process.Thiswould m ean the bob com ing straight from the foundry with a finish suitable imm ediately for use.Trying to clean up an ordinary sand casting would be far from easy and even then it is doubtfulifa suitable llnish could be obtained. The Rating N ut The rating nutism adeto fitthe thread on the rod and can take alm ost any 43
42
..â . 0
@ fon' n or shape that the constructor likessalthough it is as wt?llto ensure
inside by (Jriving a piece ofsquare
m ild steelthrough the hole.tlsing a thatitcanbeadjustedbyhandeasily. ham meralld tappillg lightly.The stetll Fitthcrod through the boband puton willbe sufficientto clearany lead that thenuttocheckwhetherornottherod migbtjustbei ntheway.Thisshould wi11naove asthe nutisadiusted,1fit notapply totubularpendulunlswitha shotlld stick at any point easc the centre tube.
C hapter 5 - E scapem ents The escapem ent is part of thc m echanism of a clock w hich is devoted to the speed at w hich thc clock works.lt consists of a coarqc.
clock.which is derived from a weight or a spring, is prevented from escaping and is converted from rotary to reciprocating m otion. The arboron specially shapk!tt toothed wheeland wllich the escape wheel, 01-as it is an oscillating brackd w ith two pegs, oftcn called, tscape whecl'is located called pallets that locate in the teeth. is connected via a pinion to thc m ain The title cscapementis used because wheeltrain.Thu.action is such thata thisisthepointwherctllepowerofthe tootll of the scape wheel is trappcd
45
@ There are m any typesofescapem ent,
and then released at regulated intervalsand thism ovem entin turn is sent back through the train to the hands. W ithout the escapem ent the
so m any in factthatwhole bookshave
bccnwrittenonthatsubjectalone.The
beginnerto clock m aking is generally train wouldjustunwind atno given only likely to use one of about four speed and the clock would be ofno types,butanyway any clock plan one use.M any escapem entswork atarate m ightwork from iscertain to give full ofone m ovem entpersccond and so if details of construction.Even so it is ahand issttedto theend ofthepivot usefulto know whatwe are aim ing for on which it runs the seconds can be and how to setaboutmaking thispart ofthe clock. counted offl
.. Fol io with balance -.' w eightsforadjustment
..
A
Crown Wheel . : .
-.
TheVerge and Foliot
. The l u ovem e nt o f t h t t s c ape wht l k lI is The earlicst forlu of escapenlent r c gul a t c d by t he p al I c t s , whi cll alv known to be in generaluse was the pieccs of basically tlat nletal, shaped verge and foliot. to a knife edge,attacl led to the verge t ha t r uns ve r t i ca l a nd is positioned so Itisa very simple device to m ake btlt t hat t he pal l et s ent e r t he teeth of the unfortunately is not known for good * s c a pe whee l . Tl l e s e pal lcts are set at tim e-keeping. Even so it is an interesting experimentto make one as anangl eofjustovcrninetydegreesto itgives som e idea of whatwe w illbe each other and as onc tooth of the looking for when m aking a m ore tscape w heelpassesone oftht,pallets advanced version.The*scapeisin the itis Iocked by thc one opposittl.The tbrm ofa crown wheel.w ith the teeth shape ofthis causes thc lockcd pallet at ninety dcgrces to the luovem ent. to be pushed outofthe vvay and causcs There is a sligiltradius ol)each tooth the folio. vvhich is a cross bar, to and the num ber of teeth w ilIdepend sw ing and in doing so it locks the tootllon theoppositeside.In thisway tht l process is repeated continuall y w itl)the foliotmoving backwurds and I l foru ards as illltzlltooth is lock'et1and i $ ul' tlocIkkltt.
palle' ts
Thkl spced at ur hich thc mtlchanislm
opklratk!sisêt(. ljtlstedbyur oightsatcach
p.
) f
/. 1 1
! ' ;
Xi13''f' '
'
O
K. ;
w er supp weightconnected to drum with cord.
@ on the ntllmberstlsed in thetrain
S,*:k k
. >' s
>x.
. .,.
end ofthtlfolit' l t-i1 Ns' llicll1' t .series of groovcs ll1 -( Jctltasa nlcans 0t-holding tlle u' cights in ptlsititln. (3f coursc thtt foliotl' nust be Nvel1 balanek ld alld thc grooves spaced evenly on klithklr sidtl so that a good balance is l' naintaincd. It is a silnple idea alld as such servtld clocknlakers weIlfornlany yearsuntil m ore sophisticated ideas cam e along, Tlle nearer the weights are to the centrethefasterthel ' novelnentwilIgo and vicevcrsa.ifthe weightsarc taken towardstlle end itwiIlslow down. To nlaktl the escapelmcnt thkl whct)l can be m adc on a flatplankland then rollcd into klircularfornland the cnds silver soldcred togdher then a cross
46
.
t...ukl
@ luinutes. Elsesvhere details w iIl btp
bar in which a holtl for thtlpivothas been drillcd is silNrtlr soldered on. N eedlcssto say itisessentialthatthe pivot hole is placed central to the circunaference ()f the wheelo antl a brassbush w illalso need to btphtted to hold the pivot. The teeth can be luachined to shape but this is an exalnple ofan eseapelnentwhere itis possiblc to carefully file the teeth to shape,w ith stlfficientaccuracy forthe dt w ice to work well enough. As a lueansofgettingan ideaofwhatclock m aking is about thc escapem ent has m uch tt) rtltlolnnlend it:collnectto a couple of whtpels to give sixty-to-one rcduction, fit a w inding drul ' n and weight to lhat and we have a crtlde elock which w i11 show secollds and
found ofhoNv to convcrtthisto hotlrs and so using little materialor til -ne a clock can be l ' nadc in this way. Itw ill notbea11thataccuratebutitccrtainly lnakes an interesting starter for anyoncwho feclsthatclockm aking is adiflicultart. A laterdevelopmentofthe verge and folio escapennent was the verge and balance,thd tblio being replaeed by :1 whecland speed was altered by either changing the driving weight or by claanging the depth to Nvhich the pallds entert!d the wheel. Ul llcss :1 replica of 1 particularclock that used tl -lt l dcvice is being lnadtl it is not solnething thatis likcly to appcalin generalto tl' le afnateur.
ztt48
@ Verge and Pendulum
RecoilEscapem ent
ltis possible to tlse the crow n whek ?l and verge antt while retaining its simplicity, ilnprove accuracy considerably.The escapem ent works in exactly the sam tl way, tlxccpt that thefolio isreplaced witha pendulum . This is m ade with a crutch in exactly the sam e way as pendulum sused with other escapem ents and full dctails of how to go aboutthosew illbe found in
RQ 11()Wr001110 t() the 113Ore COm 113On type of eskrapelnents w hich w ill btp found in m any of the published designs and the first noticeable difference is thatthe leeth arc t ztlt in the edge ofthe w I leelrather than at nindy dcgrtresas betbre.The pallets arC 111tlCh ITIOFC COm P3Ct 2nd Work frol m a pivotsituated above thatofthe :scape wlleel, w hich generally has thirty teeth,butthisw illdepend on the
the relevant chapter. Ond major differenceintheuseoftheideaisthat the ûscape w het ll w i11 now lie horizontal and so the. dircction of m ovem entin the train w illnet)d to be changed. In norm al enginecring practice we would use a pairofbevel gears forsuch a purposc,butin clock making the method isto use anothcr crow n wheel. sct in tht ) N'crtical position and locating wïth thttpinion attached to the tseape whtltrl.
@ and ifso the position can beobtainetl
train.The action is sil nilar to beforo' . one nib ofthc pal1etlocksinto a tooth and then as it is unlocked prtw ides a slight il -npulse as the result of the shape ofboth teeth and pallcts.' w hile the otherin the l' neantime is locking a t00th furtheralong.The m ovennentis such that there is a very slight backward lnovelnent as ul)Iocking takesplace:an action know n as recoi1.
(' ienerally fulldetaiIs Nvi11be given on any plans of how to lay out the escapelnents which 1n:1st be planned as a whold in orderto find the eorrect proportions. The pallet eentrcs are reconlnaended to be ata distance t)f 1.4 tinlcs thc wv hcel radius frol ' n its cclltre and althotlgh therc arc occasions vvhttn thisnlay vary w' e u,i1l tlsc itis ourtigure.A 11tllatis neetled tl4t)l1is to dravv a centre line.Iuark the position oftllc ' vvl ' lcelccntre,l measure 1. 4 tilues the raditls, l'laktr allother l' nark and wt zhavethe correctposition. Sonlctilnesthattigure of 1.4 can btlan extrenlely aw'kward (Al)e to nleasure
by the use ofsomc silnple geol nctry. Startby draw ing the circuluferellce ot' the wheel and tiom the centrc point draw two lines at forty-five tltlgrees. svhcl' e these intersect the circul -nference draw 1ines at right angles toward thc centre line. Tht) position atw1)ich thesetwo linescross is thc one where we ' want the pallet arborto be.
Assum ing the -scape'w heelwi11have thirty teeth- their position can bkl naarked on the drayving. It is llot nccessary to lmark the position of a11 thetetrth.abouttcn Nvilldo.There ' w ill betvvel' tedcgreesbetureneachbutan allowance has to be n-ladc forthe fact thattlltlre isa flat01 1each onc and itis usualto alltlu'onedegree lbrthat.Usc a protractorto putthe positionsol' lthc drauzing. Readcrs who have a colnpuler w'ith Con' lpultlr A ided Design (CAD )softsvar: uri11find that drasving thtt eseapelncnt is very t-asy indeed, tlsing 11 protractor and ruler
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with a pencil is m ore dim cult.An ajjowanceofonedegreeisalso leftfor tjw dropandthism eansthepalletsare ten degreesofthecircle. once the palletshave been draw n itis custom ary to cutoutthe drawingsand stickittoapieceofgaugeplateandto cutand 5leround ittogettherequired shape.To an engineer it m ay sound a rather prim itive way of going about things butthe system llas worked for clockm akersforhundredsofyearsand there is no reason for anything m ore sophisticated.
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Brocot Pin Pallet Escapem ent
Those readerswho w ish to go italone and to design their own m ovem ents Unlike the previous escapem ent, in m ightwellbe interested in the brocot thiscase when the palletslock on to pin pallet escapem ent, the eseape the tscape wheelteeth with this type wheelfor w hich is virtually identical there is no recoil action, hence the to thatforthe dead beat.The pallets, nam e dead beat.ltis aeom paratively however. are com pletely different. easy deviceto m akeand iscapableof They are in pairs instead ofthe m ore producing accurate tim ekeeping, norm al nibs that are found in the although itshould be pointcd outtbat previoustwo escapem ents.Halfround it is really m ore suitable for large clocks than sm all ones. G eorge Graham invented itaround 1730 and so has stood the test of tim e. lt is particularly effective w ith weightdlivenclockswherethereisaconstant Source ofpower.G enerally the (scape Wheelwillconsistofthirty teeth and the palletsspan anything from eightto fourteen teeth. The pallets are relatively easy to make and the teeth Canbecutw ithafly-cutter. A swith all escapem ents the pallets should be hardened andpolished
D ead BeatEscapem ent
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Dead flf-2t. 7/.Escapelïïent. Nf)Jt?//7(?/the /' t?f?//?ut' e unJt??r1// bv . s'j.vdegrees in ol' derthatonlvthe /ï.p willbe in contao' tu/I'//lthepallets.
/.l?-f' ?t'f)/PilïPallelé%'t't7/Jt??' rlf??1l
@ thereforcnecessary to do thework in
sections arc used and thesc ean be lnade from round silver steel.stepped to fitin holes in the arm s and tilcd or m illed exactly in half.Only theseparts need to bc hardened and the an' nscan be m ade froln m ild steeland the nibs secured with a suitable retaining com pound.
Pin
heelE scapem ent
a m illing m achine or by using 21 verticalslide on the lathe to obtainthe required accuracy. lt w i11 involve
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making ajig thatwillhold thepins securely in such a way thatthe cutter can rcach thc ccntre line of the pin. M ounting the pins aecurately on tht ?
wheelalsorequiresasimplejigtobe
m ade up.Thiscan bcfrom astiffcard A lthotlgh at first glance this type of ifone w ishes antlassum ing it is only escapem ent ' would seen' t to be the to be used oncc,otherwise m ild steel silzlplestofa1Ito m ake,asthere is r)o should betlsed.Thearm sarem adein escapcwheelassuch to eutteeth onsit two parts and are fairly is not quite as straightforward as it straightfol -ward and w illpresentIittle m ay seelm.Consisting of:1w hcelw ith problem to any one even slightly a series of hoIes into w l 1ich are versed in m ctalwork techniqucs. inscrted pieces ofhalf-rotlnd steel.in a sinailar fashion to thk l nibs in the brocotcscapennentsthe spacing ofthe French Pin heel holes is a sîmple cnotlgh proposition but it is essentialto ensure that when Escapem ent the pins.which arc usually nnade frona This too is an escapem cntthatm ight a good quality brass are halved this is prove ofintdrestto the lllotlk?!engincer done with absolute aeeuracy, It is wishing to go italonc and design his or htlr own clocke as it is straightforw ard. Un1ike the brocol O eseapem entthepinsare leftround and tbe arm softhe pallcts' hteitherside of the w heel. It is very attractive and elegantto see when working.Because % 2 2P, %% / the pins are rotlnd they are easier to m akeandifam odtrrllm aterialsuch as % R <7 Tellon is tlsed tbr the palletnibs,the probleln of lubrication,which at one tim c lmadtlthe escapem cntunpopular > o need be no problen: atall. Both types > of pin pallet escapem ent rcquire thc #C % c: A% pallets to be offset from the wheel, Cq rather than in line,as is the case w ith the previoustypes.
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tendency t() feed a tly cutter into the ast. To m ake a six-tooth The wheels ofany type ofescapem ent work too tö c ut t er i s not 8 1greatdealm orediflicult arealwaysm ortpdifhcultto m akethan t ha n m a ki ng a fly cutterand itw'illbe the norm alwheeltbund in the train, m ue h ea s i e r t o use. because oftheirshape. Specialcutters can bepurchase; which aredesigned First of alI a form cutter will be to dealw ith a particulartype ofw heel required in orddr to get the required so are only usable for the one radius.useapieceofground flatstock escapem enttype and retkrencdto the or gauge plate as it is m ore often various drawings w ill show readers why thisisso. Suitablecutterscan be referred to these daysand drillahole m ade for the recoil type of using adrillw ith adiam etertw icethe escapem ent from silver steel and as raditls needed. Filc or saw off the Only oncradiusand a straightedge is m etalleft at the side ofthe hole and leaslightrcliefonthefrontedge requiredathey are easy to m ake.The justfi Cuttercan bcmadeasa' Ily cutterbutit thatisleft:do nottouch theradiusthat is far better to use a m ulti-toothed rem ains.A slightcham fer can also be Cutterifpossible as a fly cutter always puton the top ifone w ishesbutthis is Seem s to apply too m uch force for notnecessary asthetoolisonlygoing Com fort as it m akes its single cut on tobeusedfortheonejob.Cuttheflat eaeb rotation and there is alw ays a stock to the required length and soak it
M aking EscapeW heels
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out. The besttype ofeontainerto use for the ptlrpose is something Iiktt a biscuittin and the lid w ilI notonly keep the Oilin place when notin uses but willalso put out any llamtls that m ightresultfrom quenchingthem etal.
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clean offthe scale tlzathasappeared on the m etaland w hen it is nice and brightplaceitin asmalltin.(asardine
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justmade untilthe edgd ofthe silver steelbarhasthercquired shape.Usea
tinwilldo nicely)which ishalftbllof cutting oi1 for the operation as the
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M achinty a Iittl: off the otltsidt 7 diatnetcro.j tIstsufficientto takecareof any occentricity thatthdchuck hasand then tlrill the hole for the bore: we now know that the bore is perfectly concentric w ith the outside diam eter. Gcntly run the radius tool you have
sand.Heattlle sand from underneath ori ginalform toolisonlyjustabout until the m etal turns a dark straw et ïicientcnough forthe job and needs colour and then quench it in the oil any help itcan getin rounding offthe oncemore.Finallyjustrubthetop of silversteelbar. the cutting edgesw itllttslnalloilstone to put som ething of an edge on them Thefinaltaskistopartthebaroffand this is som ething which some people and the toolisready forust). Gnd dim ctllt. M uch depcnds on tbe To m ake the actualcutter.startw ith a qtlality and sizc ofthe Iathe as to how length of silver stecl bar m ounted in easy itis and ifpossible itis betterto thethree-jaw chuck.Thediameterof use a rear toolpostforthe work.For thebar,w ithin reason,isnotim portant those who really cannotface up to the aslong as when the m andrelto which idea of trying to part off a piece of it w ill be fitted is allowcd for, silver sttpel of this sort of diam eter suë cient depth is Ieft to obtain the therd is another w' ay round things. full depth of the teeth. The chart W hen the m aterial is firstput in the shows the radius and therefore the chuck,leave an overhang of aboutan inch and a half,or forty m illim etres, butstillm achinethe outside edgesfor Sizes for m aking C utters concentricitys but don't drill a hole. for RecoilEscapeW heels Turn the radius as deseribed and then m achinea stem atthe back ofthetool; Escape W heelPitch Radiusof providing the work has rem ained in lessthicknessof Cutter t00thtip the chtlck thewhole tim e the stem w ill be perfectly concentrie with the tool. 0.05': 0 l25' ' 0 06,' O 16'' Thebarcanthen berem oved from the 0 08', 0 2'' chuck and the part saw n off and we 0 10'' 0 25.' have our shaped m etal but with a 0.l25'' 0.3125' ' spigotinstead of a hole for m ounting 0 16'' 040', iton a m andrel.
j . ' 4 , : y t i è ; )a r b q w s i v T t n e h l o u d g c k p y D m f . s r t , w I n H o i u e a 1 Q b l h g k q f d m ë r t . S % n w X T u c e M i ) W a o s l / î h C * ? g > , z q r t b m n u k w e i o . 1 d p s y a g h l f : P X c t ? e I k m w i b ' n o v u d . a r / l T f p A s h j g y c , t e i n d b r a z w l k G f o . h m s p c u / E e ( t ' ; v n d r b g a i l j o h k . s f w m x u # t y ' c e n v a i p d l r h o s j b u k t I o
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Use form toolto shape cutteredge make six cuts as show n.
Bemovem etal in frontofcuts as shown
ctltaway on radius to leave ctltting edge
Vethodrl/' z?pr . ?l' l ' uj . ;multitooth(-lftlel' .U. %esilver. $ ' /t?t ?lThesame/JrI ' ncf #/t?applies/t p
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To m ake the teeth.m ark 01#-orindex it atsix equaldivisions alltlmi1la tlatas show n i1 ' 1 thc draw ing. Fina1Iy I' nachine another fla! so that tllere is plenty of clearanckl: again the draw ings sllow Nvhat is required.W e should now'have six sections evenly spaced and the toolwillwork like this, but if the square edges have a sm all relieffiled orm achined on thcln itwill work evcn better.If howevcr you are notentirely confidentofbeing able to get these re1ief angles without dam aging what will be the cutting edges,leavethingsasthey are.Finally repeat the hardening and tem pering exercise as detailed already and yotl have a eom pleted ûscape wheelcuttcr. lt w il1 not be as efficicnt as a professionally-m ade one, these have sixty tceth as a rtlle,butitwilldo the
w' ith the pallets bal lging up and dow n on thcnl fortnvnty-four hours a day. NVI ' Iile thereforc itnlay be desirable to tlst l soluething a Iittle thinncr to save weight.doing so cotlld defeatits ow n purpose,as itis m ore likely to distort during operations. Som e readcrs m ay nothave sum cient equipm entto m ake the above tools or not feel entirely conhdent about so doing.Itispossible to file the teeth by hand aftervery carefulmarking out.It got )s w ithout saying that a grcat dcal ofearc isnccded and in particularitis cssentialthatthe straightsections art l really that and are not angled in any way.If: 1sm alltem plate ism ade ' hrstit can bc used to check thatthe radiusof cach tooth is correct . it is alm ost
job and afteral1itisunlikely to be impossibletodosowhenjustworking used forcutting m ore than one ortwo whcels.
W hen cutting whtrtlsand in particular this type it is essential that they are well supported to as near tlle point where the teeth are being cut as possible, partictllarly w here hom c m ade cuttdrs of any sort are in use. The pressure reqtlired to cutthe teeth, even though we are only removing a little m aterialata tim e isconsiderable and the tool w ill tcnd to bend the metalasitcuts.Thatisthe lastthing we need.Generally *scape w heels are m ade from m aterial of 1.5m m or 1/16ins thick and we are torn between two possibilities here. To get the m axim um efficiency the %scape wheels need to be as lightas possible
to m arkings. The tem plate can be m ade from a piece of card, but som ething m ore perm anent is preferable and plastic is ideal. A suitable piece can be obtained by cutting up an old cretlit card and finishing the radiusa w ith an em ery board ofthe type used form anicuring. On m any very old clocksa11the teeth on the wheels are hand cut, and in comparison to a greatw heelan escape wheelisvery sim ple indeed. To com plete the escapem ent w e require the pallets and to lind the size and shape ofthese itis necessary ' Iirst to draw the necessary angles. The pallets can then bc ctlt out, using gauge platc to make them . There is really no way to m ake them except
W jth a fiIe and sau' .althtlugl l perllaps roughing Out could btl done on 11 rnilling l' nacl line.ltiscssentialthatllle Pallets are m ade accurately and tllat thenibs-which ardthe pointdd pieces thatstick outhave polished working surfaces. A s m uch polishing as Possible should be done before they are hardened butin doing so the shape and size m ust be m aintained. Final polishing can be com pleted aftcr hardening and m ethods of so doing willbe discusscd elsew here.
The j -inal task to krolllplctk ? the escapelncnt will be to trroh;s otlt the u'hccl,' svhen thatis colnplettxd. lllot,nt itolla colletand sccure itto tllt ' tpiq' ot. Itcan then be tdsted.tlsillg a depthing tool,to check thatthe pallets w iI1do
their job. As tlzkly are Imoved backwards and forw ards the action should be suflicient to slowly rotate the wheel.
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C hapter 6 - T he G oing T rain & M otion W ork Thegoing train as itis properly called connects the power unit,whether itis a drum and weightor a spring and fusee,to the escapem entvia series of wheels and pinions. W hen first looking into a clock itappears to be a
param eters in order to m aintain tim e. Various com binations of whecls are used but these m ust be in a logical sequence. Let us start w ith a hypotheticalclock,although the train usedwillbeonethatisquitecom mon.
jungleofwheelsandpinionsanditis The great whcel connected to the this apparent disorder that freqtlently putspeople off m aking orrepairing a clock. W hile these gears and pinions m ay be in a numberofcom binations, the form ation isthe sam e forvirtually every clock and in fact there are noWhere near as m any aS it Seem s at srst glance.The great wheel,which has already been discussed when dealing with the power,drivesa pinion which in turn drivesthecentre wheel. The pinion connected to thatgoesto a third wheeland the pinion forthatis in turn connected to the escape wheel.
drum arbor has ninety-six teeth and w illconnectw ith an eight-leafpinion on the sam e arborasthe centre wheel. The centre w heelhas sixty-four teeth and as itcarriesthe m inute hand must rotate once.This in ttlrn connectsw ith an eight-leafpinion on thethird wheel arbor,the w heelfor which has sixty teeth.ltconnectsto anothereight-leaf pinion on the escape wheel. W hen designing a train itisessentialthatthe escape wheel shall m ake sixty
revolutions (seconds) for each one revolution of the centre wheel
We have therefore just fourwheels (minutes). To check this multiply and three pinions,which is an easy m anageable num ber,particularly for anyone versed in engineering m atters. The wheelcom bination willvary in Sizedependingonthesizeoftheclock being m ade and on the whim of the designerbut m ust conform to certain 58
togetherthe num berofallthe teeth in the driving wheels and divide the answerby the numbersofleavesin the pinions,multiplied together.W ith the exam plethatisshow n in the appendix on page 121,this works outas sixty w hich is what w ant; any 59
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@ com bination can be checked in this way to ensure thatthe train isgoing to b: right. In addition lo this it is possible to work outthc size ofbarrel and length ofdriving eord thatwillbe required. If a shorter pendulum is uscd it will beatatlessthan a second and from the table itispossible to work otltatwhat speed a givc11 Itlngt1 ) w'ilI bt lat.
bLltttA 112ke a llntl%' ol' nelltto 1112 ( 2ase thatone particularly wants.Rcferent?e
to thetables(st )eAppendix pagc 122) can enable usto tind outthe speed al Nvhich a pendulum of a given lengtl) w i11bcatand whatwheelcom bination is needed to m ake the clock work
accurately. Althotlgh a table o#' colnmon wheeltrainsisincltlded.(see Appendix page 124)itdoesnotmean that they are the only combinations Suppose thercfore the major factor avai1able; it is quite possible to behind tbe dcsign ofa clock is notas calculate one foroneself. usualto fita case round the m ovem ent
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rhe train then setsthe clock so thatit ticks Off the lminutes btlt m ore than thatisneeded:evklry clock mtlstshow the hours and solme even incltlde a calendar,whileothers have phasesof the m oon. lt is not intended to deal with these latter factors or striking m echanislms but it is necessary to arrange for the clock to indicate the Passing hours as wellas lllintltds. As the m intlte pivot does one colnplete revolution once every sixty m inutes,Nvhat is needcd is a twelveto-one rttduction.in (3l' tIel'to lllark off thehours.Thisisobtained in thususual way by using a pinion and u.ht?eland thereforeany pinion and wheelwith : 1 m ultiplication 01- tw clN' e w i1l do. Another factor comes into it as wtlll and thatisthc sizc thatlhtthourwheel w ilt be, for exanlple u'ith : . t six-leaf pinion the hour u' lldel u'ill have seventy-two teeth, u?hich is klui1e m anageable.M ake thu pinion twelvc leaves antl the hour whet?l Ileeds a hundred and forty-four tceth, a size which is likely to be nltlch too Iargc form ostclocks,Probably the targest size that can be coped w ith in m ost movcm ents w il1 be an k lighl leaf pinion and a nindy-six-tootl) wheel and even thatis on the large hlizc.lhis leaves a lil u it of six or scvb en-tootl) pinions as practical propositions as above thatthings w i11becom c far too unwieldy.
becolut,s a c' ase o1-connecting tht lse two to the pivotthat wilIoperate the hourhand.The obviousallswerwoultl sctll ' n to bttto puta suitablc piniol lon the arbor of the l' ninute w'heel. connecting it w ith a wheel thal w i1I give a twelve to one reductilln on anotherarborimm ediatdly bclou'orat the side and putthe hourhand on that. There is only one snag,if we has' ea pinion or a w heel rotating i11a clockw ise direction and conndet another directly to that,thc addition one w ill rotate in an anticlockw ise direction,Nvhich is nota greatdeal()f use Thereforc two additional arbors w ith suitable wheels and pinions arc ndcdedethe lirstto change rotation to an antitrlockw ise direction and tht? sctrond to trllangt zitback again.111the llntlitntillatl any llcccssary redtlction ckt! ' tbe il' 1t-(' ,1 .porf 1tt-(1. Sonltlold clocks and no doubt solnkl bdillg l' na(. lc atpresentasu' ellIlaN' e tllut I ' ni1)uttr hal' l d ilnluediately bkllou'tllt p hourontl.Thesc do nothave tht lgoing train arrallged i1' 1a straight Iint),as is the l' nore usual arrangclnent. Atlditionalarbors witl a pinions and a reduction wheel are then set at an angle to enable the hour arbor to be placcd in the centre ofthe m oN' em ent. The fsnished rcstllt is quite attractivc and worth considering.
Because space is generally linnited lmostclockshave the hourand m inutc wheelin the sam e place-tradition also So far so good; we have no dotlbt probably has a part to play in tlltt m ade up our m intls of the best arrangelnent.The sam e ndeessity to oom bination forthe train and itnow change the direclion orrotatiol)is still
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eonnecled to a hardened steclpinion. on a pivot tllal is generally m ade 01* brass.The systkllu sklen' lsto has' d stood t he t e s t of t i np e, bt l t c oul d be i l l l proN'u' ti arrangeanidenticalwheeladjacentto itwith a pinion attached to itso itwill nrith the use ofm odern naaterials.bLlt rotate atthe sam e time.As the w heel then clock m aking is a traditional m ates directly w ith one fixed to the industry which is one reason tbr its m inute pivot it will rotate in the fascination. reverse direction.There isno arborfor W ith the pinion in plaee it is now a this pairto run ()n and so a shortone ' isprovided and they areallowed to run case of connecting it to thc hour free on it.It has a lhreaded cnd and whecl. which is donc by sinnply screws into the frontplate,tiequently allowing the wheelto run loosely ()11 the other etld stlpported by a bracket an extended collethtted to tlle lninuttl with a hole to actasa bearing surface. wheel.The hourwheelin turn istitted In otherinstancestheremay be justa to a collet that is also a bearing of !d length to ensure itruns true hole in the end ofthe pivot.through extendt' a nt l t ha t there is sutsicient surfacc 1t' which passesa splitpin to preventthe al l ow f or wear. The collet on thc wheel and pivot from conning off. m i nu t e whc elhas a square on the entl Bearing surfaces of course should a nd t he ha nd w'illbtla push-titon this. always be of differenl metals and in Thu t hot l r ha nd can then bc ' l ittcd this case w' e have a sligh!allom aly as di r e ct l y t o t he e ol l et t ha t s t l ppor t sthc the revt zrse whttt alisgenerally lnade of h our wheel . Bot h hands ar e now' brass and w illbe running w ith a brass r t l nni n g f r om a ce nt r al poi nt . wheel while at the sam e tim e being presentand lhe u' ay lhis is done is to fit a w hcelwith a suitable num ber of teeth ol1 the nlinute pivot and to
63
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64
65
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C hapter 7 - D ividing Accurate dividing is a prim c requirem entwllen cutting u' heels and there are a number of ways of tloing this.Any reader who owns a dividing head w illhavt?no necd of any adq'ice
onthesubjectandcanpttssontothe section on cutting the teeth. Experience show's tllat i1 2 genera1 dividing heads are not usually found in the hom e workshop.they tend to be one ofthe lastpieces ofeqtlipm entto
be bought,and where they are tbunct
divisionsthatcan be oblained.Few,if any lathes will have change wheels w ith m ore than seventy teeth. which m eans that seventy js the highest nunïber of divisions that can be obtainetland the tlivisions obtainable on the slnaller wheels are extrcm ely linlited.In his book -Gears and Gear Cuttingq, lvan Law describes an excellentset-up f' br com pounding tl' )t l dividing gcars. thus giving a m uch wider rallgc (. Afdivisions.as welIas a m ass of inform ation on gear-cutting m ethods.
in generalthey w illbe hom e-made.It isnotwithin the scope ofthis book to gointohow tomakesuch adeviceand in facta fulldividing head isnotreally W e m tlst a1so consider thc 1arge ntlm ber of lathe owncrs who do not necessary forclock m aking. have chang: whecls. For examplc M any readers will be quite fam iliar m any of the sm aller lathes that are with the use of lathe change wheels quite popular forclock m aking do not fordividing and in som e instancesthe have any, neither do those that are idea w illbe quite good enough forotlr stted with gearboxes. M ost have a purposes. Consisting of sim ply a hollow m andrelthat could be uscd to m eans of holding a lathe changc hold the wheelin position btlt it will wheel firm ly in the m andrel of the involve purchasing special gear lathe a detent or pointer that will' l it whcelsin orderto use the system . exactly in thc teeth of a change wheel and secured to a perm anentpoint on The alternative is to use dividjng the lathe;the idea has serx' ed m odel plates which are m orc acctlrate than engineers well over the years.The gearsantlcan beeasierto use.W etend m ain problem isthe lim itcd ntlm ber( . 7)- to think of dividing platcs as partofa 67
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dih. zîJil1g head but 11)is necessarily so: tht ?y can be sccured directly to the Iathe nlandrel in the Sam e Nvay aSa gear.In 133a1y V'aySt1is is bettcr than using a dividing head where there is always the problem (af backlash in the worm gear to worry about. M ost divitling plates have a range of divisions on each platc, giving tlexibility as wellas accuracy. They can be pttrchased from m odcl cllgineering suppliers or suppliers of
speaking itwould be betterto go to tlle latter. as tlle plates sold tbr gelleral l motlel engineering purposes are lutss likcly to have the required nulnber ()t' divisions. P1ates bought from clockmaking sourccs w ill often havc exactly the rightnunlber of divisions for a col nplete clocklmak'ing trainm usaning tllat only one plate is requircd forthttvvhole movtln-ltrnt.
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r Having seribed lllc circle it is necessary to refer to 1 , chord chart.It
sounds obviousto justmeasure thc circum fkrcnce and then divide by the required ntlmber but this does not works as the distance lneasured between two points on the scribed circle,when using dividers,w illbtla straight line across the two points ratherthan round them .A chord table
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figure for num bers of divisions, assum ing the circle diam eter to bc one. To obtain the required figure angle and allow ittojusttotlch the silzzply m ultiply thelength ofchord by disk while rotating the Iathe by hand. the diam eter of the scribed circle. A handl: that can be secured in the Having . established the length of the mandrelis usefulforthissortofwork required division, take a pair of aswellasa num berofothertasksthat dividers that have nice tine points on we come acrosswhen m aking clocks. them and setthedistance by reference
@ to a m icrometer or vernier gauge. by tle tim e the 1:1st one is rcached a M ake a 1ight centres punch mark wholem illilntltre hasbeengainedand somewl lere on tle scribcd ttircle and this is now here near accurate enough m ark Off the divisions, starting and so some m eans of cllecking tllerefore tinishing at the centre-punch mark, is required.Supposd we are to divide Lightly centre punch each the plate into sixty divisions, Hav'ing intersection.It is advisable to use a set the dividers as suggested with a magnifying glass to setthe dividers m ierom eter or vernier gauge and andto makethepunchmarks,inordcr madethehrstindcnton thcline,mark off but don't spot thrt ztl divisions. to gettheaccuracythatisrequired. Preferably using another pair of NonmalImarking-outluethodson a tlat dividersso thatthe originalsetting can plane dem and thata11l' neasurem ents be m aintained, check the distance are taken from a single datunn, across the three m arks.lt should bc som ething that is not practical when cxactly the chord hgure for twenty dividing u circle. Tllcrefore the divisiolls.N extm ark offanothcrlhree possibilitikls of l' nultiple errors arise. divisions and cheek again thd w' holc For exam ple if the tlividers are one distance- using the clnord figLll-tl for hundredth ofa ntillil -netre ovcrsi/tlalld tkln.Any error in the originaldix'ider there are ahundred divisionsrequirdds sctting n'illntns show up and suitablc
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@ adjustnRentsnzadeifneed be.W'hen it plate shouI(1 be sprung loaded if is rightand l1kltbeforesImakc the spot lnarks w ith the punch.Rem elllberthe larger the plate and circle tlsed the greaterthe aceuracy w illalw aysbe.
possible-Iargely as a mcans ofsaq'illg tim e,ratherthan tbratrtruracy whieh can stillbeachieved ifitisa ptlsh-fitaslong asitcan bc locked in position. To keep unscrewing and then Once the m arksare m ade itis sim ply screwing up the devicc isvery tedious , a case of drilling though the plate, particularly if the division is for a using a drill of the same size as the large num ber of teeth rem em bering detantthatitis proposed to use. lt is that we are talking in many cases of essentiatto cnstlre the plate istlatand wheels with 21tooth countnearing tllc atcxactly nindy degrees to the drill hundrcd. when itisbeing drilled and in orderto ensure this it m ight be necessary to deburreach hole asitism ade.so that the burrsdo nottiltthe platew hen the Securing the D ividing nextholt!ism ade. Plate
Nlake a series ofsuch k 2ircIes in the 1)late,pret krably ofthe nulnbers that w illbd ttsed in the clock train. Do bt ' t careful to ensure accuracy and l' neasurc at least twice, prefkrably three times,before l' naking any luark and then proceed as abovc. A1I the holcs shotlld notonly btpdeburrcd on the sidkl they brklak through btltalso slightly counterstlnk on the face, to facilitate the drilIentering u' llen they aretlsdd.Thcdetantshould beagood fit in thc holessbut not so tight that force is required. 1f it is tapered slightly thtt good f st willbe ensured bu1thc laper mustbe stcep enough lo prcventthe detantfrolllbinding in thk! hotes.
The sct-tlp fbr sectlring the div'iding platc is quite easy to m ake. A piece of thin-walled tube ofa diam etersuitable to be a good ptlsh-fit in the hollou' m andrelis needed and thisshould be about four inches or a htlndred m illim etres in length. If tube is not availableitw i1Ibenecessarytodri11or bore a lcngth ofsolid bar. In one tpnd litathreaded pieceofbar, aboutthree quarters of an ineh or twenty m illim etres i11Icngth. The diameterof thc thread w illdepcnd on thc diam der ofthetube,butaboutthrecquartersof the bore isideal.
A tapcrcd plug isfitted to a lcngth of threaddd rod.orstudding and a hom em ade nut. solllewhat larger than Itis essentialthatthe detantset-up is norm al pulls the tapered scetion up securkld to : 1position on thc Iathe in tight.The nut docs not have to be such a way thatitwillnotl' novt)outof hexagon itcan be round and knurled position.The actual dd ant that will and for extra security a num ber of locat: witl the holcs in the divr iding holcs ca1 ' 1 be driI1ed round the
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The device can also be tlsed on : 1 sim plesdt-upon them illing m achine, whichrequireslittlenaorethan ahefty angle plate w itb a hole, to accept a m andrelto hold the lathe chtlck.Thk) otherend Isthrtladed so thata nlltcalk be used to tighten tht lgearwheelor
dividing 17lllle lhat is i!' l ustt 8111(. 1a detant can be l -itted il' l :1 bl-acket strrew'ed to tl' !kp sitlc of thc unit. . 4 sere' wz is incorporatcd to lock the fnandrelin position once the division hasbeen set.
Dividing can also becarried outw ith a rotary table htted w ith a m eansof holding a m andrel centraIIy.Ustlally this m eans making a device on to whicha lathdchtlckcan befitted.Itis ditlicultto setupthesystem aceuratcly anditisbetterthereforetoonlyusk,the rotarytablutfbrmaking djvisionplates or,ifno othersystcm isavailable,w ith which todotheacttlaldividing.
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C hapter 8 - W heels & P inions In norm al cngineering practice,what is known as a whecl by the clockm aker,would be ret krred to asa gear,som ething with which weareall fam iliar, although the- whecls in a clock diff kr in shape and forl' flfrom thegearsin a m otorcar.Therc arctwo types ofteeth:involutc and cycloidalthe form er tlsed in dnginccring Nsb llel v itism ore tlsualforthc sm allcrgcarto drivc the larger one and the involutc form gives: 1bdtterbearilpg stlrface tbr this purpose. I11 clock m aking the cycloidal type is used becausc in generallargerwheclsare used to drivtl
thc snaaller oncs.w hich are known as pinions and the tooth pattern ereates less friction.ln 1111 things to do with clock m aking there isa constantbattIe to reduce both friction and weightof conlponents in the search 1br efficiency,Engineering-typc gears arc describcd in Britain, Alneritra and I uany other cotlntries under the ttrl -l' l dialnetraI pitch or DP for short. N' leastlrclncntis#bund by dividing thc ntllllber of tetltll into the pitch cirele dialuettlr. ' w hitlh is a positi(311 Nvllere the tecth nAeet. The position is llot visïbleu'htln looking ata gear,o41ly by
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taking various m easurem ents of the gearteethaetc.can the actualposition can be found.The m odule system uses thereverse ofthisand isthe nuluberof teeth divided by the pitch diam eter;it is entirely a m etric systenR, whereas thcD P system can be applied to either im perialormetrie.
W e are only going to deal with the module system asin clock making itis all that is necessary, although the clock repairerm igbtwellnecd to usd 170th w hen repairing a very o1d clock.
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needed are a m ultiplication of thtm odule number.Allnecessary details for working out the wheel from the m oduleaswelIasthe m odule from tle the wheel sizes are ineluded in the charts.The system is quite Iogicalantl the larger the m odule num ber, thc largerthe teeth willbe.U sing alarge num berhastheadvantagethatwhcels are less easily interrupted in their operation by dirt but large m odules nattlrally are not suitable for sm all clocks,such ascarriageclocks.
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Terminol ogy forobtaining measurements and module numberofwheels W heeland Pijlion Proportions W heel s Modules = Pitch diameterin mm divided by the numberofteeth. DiametralPitcb= numberofteeth in a wheelperinch ofdiameter Addendum = distance from pcd to tip ofteeth (1.35 x'module) Dedendum =distance from pcd to base ofteeth (= 1.57 x = module 0.45 and 1.1to 1.5 and 2 x modulefrom O.5 -1 J(Shortform = /.07 x module) Pitch Circle Diameter = numberofteeth x m odule Outside DiameterofBlank = Numberofteeth+ 2.76 x module RootDiameter= Numberofteeth minus 3.14 x module formodules 0.45 and 1.1to 1ab Num berofteeth m inus 4 x m odule form odulesO.5 lo 1y0 7-00th Thickness= 1.57 x module Addendum Radius= 1.93 x moduleformodules 0.45 to 1.1lo 1.5 Includes N/Y Z'/'form Full7-00th Depth = 2.95 x moduleformodules 0.45 and 1.1 to 1.5 -3.38 x module for module 0.6 to 1.0 Pinions
Alldimensionsare ratiosofthe module. Pitch Circle diameter = numberofIeaves Outsidetipdiameters 6 = 7.71.7 = 8.71,8 = 9.71,10 = 11-61,12 = 13.61
Kppl-dl. p. n. Jp. !. tr m 6 = 2.5,7 = 3.38 = 4.2,10 =5.9,12 = 4.8 .
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Lea-fThickness 6 -8 = 1.05,IQ - 12 = 1.25 Addendum Radius 6-8 = 1.05,10 - 12 = 0.82 7-00th Pitch Ratio 2-8 = 1/3,10-12 = 1/5 A- ddendum 6-8 =0.855,10 - 12 = 0.805
gvdendum 6= 1.75,7 = 1.85,8 = 1.9,10=2.05,12 =2.10
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Exeept in exceptional eircunRstanees wheelsare l' nadtnofbrassand 1' 01-m ost norl -nal clockl making purposes and ccrtainly when conlpared w ith norlual engineering practice. thc lnaterial used is of a very thin section. This creatcs its own probleln wht?n cutting teethasthereistendency t brthemetal to bend away frolm the cutter if any attem pt is l ' nade to advance it too rapidIy, or if the materia1 is not properly supported. Beeause of the thin l' naterial uscd tht? wlletll 11711st alwaysbe supportcdonacolletwhen assenlbled on the arbor in order to give a greater supportstlrface. lf one rcads any of the exeelIellt books on clock l making and repairillg thatwere w ritten m any years ago itwillbe seen thatthe usualmethod of holding the wheelon thecolletwasto rivettheend .
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l netal expanded and held the urheel firlmly in position. N tnvadays a far better idca is to use a retai1 -ting colmpotllldo 'not only docs this give a secure bolld btltïvith a smalIam ount of heat the bond can be broken if required. The sam e applies w hen litting the collet to the arbor, rather than use a force fst,a tiny drop of com pound on a unit that is a good '
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slidinglitwilldothejobfarbctter. The bcst brass to use is knosvn as eolmpo ()r engravi11g brass and is stocked by both clocklnakers' suppliers and many modeI cngineering stlppliers as w el1. Suppliers of clocklmaking lmaterials often willbe abld to supply itas round blanks of the outside dialntlter required.Failing thatwe art ' tleftwith two choices, 'itcan eithcrbe cutfrom
@ rotlnd bar. nnachined to size and contrentricily.It
sheet or sliced from Although engraving brass is not available as bar stockethe m dtalw'ilI generally be fonnd to b: quilc suitable.It is shedt l' naterial that is unlikely to be ofthe required quality. ' Ib cut from a sheet of suitable m aterial it w ill be necessary to first make a centre and then l nark off a circle a little largerthan the outside diameterofthe blank,which can be cutout,using a piercing saw or better still a m ecbanical scrol1 saw. Thc centralholeisdrilled-tothesizeofthe collet on n,hich the whecl w i1I ultimatcly bc mountett ensuring itis at ninety dcgrees to the facd and the disk and m ounted on a stlitable m andrel to be put on the lathe and
u' i11bcnecessary eitherto lnakk ldisks thatu'il1' hton theoutside of-the blank to hold il ' lirm ly in positionsbecause the dialneter of the hole for the l ' nandrelwillbe sm allitisessentialto avoid too m uch torque being applied by the toolwhen trying to m achille the blank and thcwashersw illcounteract this.lfonly the m andrelin the smal1 hole is used there w ill be tw o tlnwantcd effccts, the first and m ost obvious isthatthe blank w illtend to bend as pressure is applied. Thc secolld less obviotls one is that no m atter how carefblone is when doing the m achining it w il1 be alm ost ilupossible to stop the blank from catching while thc lathe contillucs to
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havc the atlvantage of being sm al1. which l n akt )s thel' n particuIarl). ' suitable for use on a slnall lath:. A lthough they are very expensivethey arem adeofhigh-speed steeland w ill lasta lifetilne.Cheaper cutterscan be obtained' .these are dcsigned to l iton large horizontalm illing m achinesand C utters although fitm ents can be m ade t() cutters are available enable them to be uscd 011 lathes and conlnlercialIy and specialist clock verticalm illing m achincs, the set-tlp suppliers should be able to supply a is rather btllky. Frequently too thesc suitable cutter for any l' nodule that cutters are for illvolute gears rathtlr n' lightbeneeded.These specialcutters thancycloidial,so checkbeforebuying. som e distortion of the holc and no luatterhow slightthislnightbe itwi11 lead to lossofaccuracy.lfthe work is supported and gripped by suitable washersthisshotlldnotoccur.
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Toolm ade from silversteel, hardened and tem pered.Obtain radius with drillormilling cutterforaccuracy.
Body from mild steel, cross drilled fortool, drilled and tapped at base forscrew to hold toolsecure
H om em ade C utters ln chapter5detailsform akingcuttcrs forescape wheelsweregiNtn;itisalso quite possible to m ake ones ow n euttersforwheels,using silversteelor gauge plate, w hich w ill be quitc suitable for making the num ber of Wheels required for a norm al clock. W hen m aking cutters rcmemberthat We are notgoing to m ake a t00th but
tom achinethegapbetwcen tw' o teeth. shaping half of each in doing so. Com m ercial ctltters are of the rotary type w ith the shape tln the periphery, which isthen divided into num erous cutting edges. Em ulating this in the norm al hom e workshop w i11 be im possible and so itis bestto aim at six or eight cutting edges, or a tly cutterwith a single bladc.To m ake a 1' rl1. l1t1-t00th cuttercalls forsom c form
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actltlrat)y neededs det1 )i1s of the required radius which is as shown in the tables on page 79, 1.57 x the m odtlle. Therefore beforc any calculationsfbrteeth orcutters can be m adc it is necessary to Grst Gnd the m odtlle that is to be used.Gcnerally this wi11 be show n 011 the draw ings, butthere are instanceswhere thism ay not bt l the case. For dxam plc the author u' as intcrested in making a regulator some dctails ofwllich wert show 1' 1 i11 an old book. OnIy the otltside diam ctcrs of the whecls and the num bersofteeth weregiven and it wasnecessary to work outthe m odule
a dril1is obtainablc.forexalnple a ().5 l' nodultlhasa radiusof0.965111114so t(' be exact wc nced a drill 1.931 1317) dial -neter,A standard size is 1.95l ntll and that w illbe nearenough f br otll' Purpose, if necessary IAfJ great harn) would com e from uging a 1.9111111 dialneter driI1- which is easier t() obtain.Forthose who like to work in Inlperial lmeasurdm cnts 5 64ins. wotlltlbe a suitable sizc.
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' W hether or not to l' nake single o1 ' nlulti-point cuttcrs is a nlattt)r t)1' individual choicc' m any people alv qtlite successful w ith ' lly cutters antl s et ? no nee d t o got t o the bothcr ot' inorddrtotaketheprojectfurther. 1naki11g nnuIti poi1 ' 1t O1' 1es, ' W ith kl The gap between tlc teeth ofa wheel single-point cutter cutting the blallk isthe sal me astht)thickness ofa tooth mustbe done l m ucllmore slowly tlall and is one ofthe hgures reqtlired;the w ith a l' nuIti-point one aIthougl) second is the overalldepth and thirdly rotational speeds can be as hig1, 1 t)I' thc a11-im portant radius. Tw o eNzen higher.Thereartlntllnerotlsidtttls expressions crop tlp hcre. addendul ' n on Ilow to cutthe blankss 'generalIy il and dcdcnduln. They acttlally speak willbe a lnatter ofwhatcquipm entih ; fortllcl mselves' ,addendum is 81figurc availablc to the individual.The blal lk added to thc point of the pitch tran be held in a sel-up on the verticaI dianneter and dcdendum is figure of slide of tht ' l lathe. with the cuttcr the distance below it.The radius on a rotating in the chuck.orthc blank cal ) wlleel is the shape of the addcndulm behdldandindexed i11theIathechtlck and is the only dif-hcult part we arc oracollctand thtlcutterrotated on tht? likel y to come aeross w' hen nlaking a Ialhe saddle.To tlo 1lisa device hast() cutter. thtl other ligtlres bcing qtlite be l made in w hich to rotate tht?cutter. straighttbrward.It is not going to be Yearsago nnodelengineers uscd to usc easy to getthis raditls with a file and a drivc frol' n an overhead beIt. ' absolutely il mpossiblc w itl)a grinding nowudays w ith the ready availability whektl unless one can be purchasetl of cheap small elcctric nAotors it is that has been specially shaped.The l' nuch easier to l' nakc thc arrangem ent bestway ofgetting itacetlrate w i11be sclfpowered.An easy way isto l'naktr to drill a suitablc sized hole and use a bracket for a small nlodel l'naker-s that.Theradiiasshown il1thechartdo drilland to l' nountthaton the vertical 85
84
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lathe. ln the ease of the lnilling m achine a vernierheightgauge can be used to setthecutterin relation tothe blank.ltisalso essentialto ensure that there is no shake or backlash on the mounting used for the blank as this too willleadto lossofacctlracy,
Pl @nl @ons
slide tbrheightadjustlnent.There is m illing attachm ents tbr a sm alIlatlle little involved in doing so;any silnple bracketw ilIdo as Iong as itwillhold the drill' l irm ly in place.M any small lathes are now available w ith m illing attachm ents and these are idcal,as it m eans the blank can be held in the chuck and the cutter rotated on the m illing attachm ent. Generally thcse m illing attachm ents are fixed to the lathe bed w ith :1 bracket and : 111 adapterwillberequired to 5x ittothe saddlc so thatitcan be traversed as it willbe ofno use in a lixed position. Owners of larger Iathes l' nightfind it worthwhile to invest in one of these 86
and fitting it to the cross slidc with lt bracket. Those w ho havc m i1Iing machines can use a sim ple indexing arrangem enton the table,asdeseribdd in chapter 7,with the cutterm ounted in the m andrcl and w ith a1l thcsc
alternativesajob thatwasoncequitc difticulthasnow becom em uch easier. It is essential that the cutter is set at the exact centre height of the blank. Norm al methods of obtaining centr: height are generally not accuratc enough and itis bestto use a scribcr mounted in the chuck or colld of the
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m ust work out right if the clock is going to work properly. Enginedring practice tells us that the m ore leaves the pinion has the slnoother it w ill m esh and rtln with a gearand there is no doubtthatthis is equally tru:w hen clock m aking. Therefore ideally it would be nice if twelve-leaf pinions were tlsed al1 the tim e as it would m ake our clock run smoother,Sadly because this would m ean very Iargu wheels this cannotbe and we are far m ore Iikely to be m aking six oreightleafpinions-in factthe m ore effieitlllt twelvc-leaf type is rarely scen atall. Therc are also three differcntprolilcs and althotlgl l in general01 115/tu' o are used itishighly probable that:1design nAighti2alIforadit' ferenttype.Pinions Nvith a greatklrnulnber ofleaves use a diftkrentprofilc to those w ith :1lcsser num bel-- thkl 1caves being m ore roundcd o1lthtrhighernul mbers.
The pinion or sm allgearsofa clock set the builder differellt problelns to that of making whecls. lnstead of easy-to-machine brass, silver stcel is now the m aterialto use and ratherthan cutting throtlgh 1/ '16ins or i.51' nm thick materialthe teeth,or leavt?s as the clockm akercalls them-w i11bklat abouthalfaninch orl2m m Iong.The shape ofthe leaves also diftkr slightly from thcteeth ofthe whccl,with thc resultthatthe cutterused forwheelsis notgoing to be suitable forthe pinion. There are considerably fewerleavesor teeth than on a pinion,w ith ntlm bers varying as a rule from six to tw elve In the past the k rlock-lmakcr NvouId . and just occasiollally for special l'nakd pinionsfrol-f'lpiniol)w'i1-:-w-llic1) purposes there are instances of four was a Iong length of m etal u'ith the leaf-pinions,although there isno need leaves already shaped.lf there were to worry about those. Thc train of too m any leaves they would simply
c t l e to c n o e ro e t c la p n o d s i h t i a o n l . ' mt c h r t l h l e n o g t h e r s t h t a o @
Inaking :1 suitable cutter a ' vt)l. y. dif' f icultproposition,w hilc theteeth t)j' 11a(1bt lt)n suitablydoctoredwotlldthen asvheelare straightthose ofthe pinio)l becutoff,polished and taken into use. tapor inwards. Because of the snlall lt was a highly-skilled process and num ber 0f teeth and the m ostm odelengineers willfeelm tlch diameter- thistaperdoes notm ean a1) more at hom e if they l nake their increase il) area at the root- insteatl pinions by m ore conventional there is a decrease which actually m ethods. makes the cuttereasierto m ake rathcr than harder. The sam e methods arc A sim ilar system of nleasurem ent uskcdtomakethectlttersaswerctlsk zd used in the sam e w ay as for the fbrtj j:w heels.Ifa flv cutter is used w heels- but the lcaves are much m ore care m ust be ta' ken because ot' thillner than are the teeth ofa wheel. tl ak, leneth that has to be tnur ellk ld. This is to allow sufficiellt moqrem ent vjycrut-or ' -/k c a good supply of euttillj z i l110 Ploarance ft nrtlle pinion to rotate jjt jjk!isussentialtonreventthecutttl). w ith thc whecl-w itllout creating too V ,jljqyja m ustbc tkd ' vcry slow ly,froll) luuch fkiction,so while thc width ofa ovel.j at cating. ' f'he pinioj) m tlst but00th On ' W' hcel a''d tl'o Space in ,rted ateach end during cutting between is equal in the casc of a suppkions,othulavise itw illflex aw ay. operat Piflion th0 leaf takes ond-third of thc tyom the cutter,resulting at tlltl very' area adpd the space the reluaining two. Icast in a bad profilc if not acttlally ' This applics to pinions with six to ten tnkzj,kjing thc work. leavcs. above that thc Iea. f occupies tuo-t-itths and the space the other ordcr get a good snaooth threc. opcration itiscssentialthatthc leavcs Of Pinions arc givcn a good polish.. Cutttu's fbr pinions can be purchased otjaumvisu they wi1lbe dragging on the but again are vcry expensive and u cth of-thc wheels. No luattcr hou hollltl-llladc ones wilI bd quite carejulone is when ctltting.the end satisfaclory fornlaking a singlc clock. resujt wi1l always result in a ragged At firgt glance itwotlld appear that finisj-l of varying degrees . Thi s m ay
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notbe obviotls lo thtlnaked eye.but look at itthrough a magnifying glass and itcanbeqtlitehorrifying.Possibly the best m ethod of polishing is to m ake a sm all profiled wheel from brass,using the sam d cutterthatwas used to cutthe pinion,coatthisw ith a m ild abrasive com pound and rtln it along the leaves tlntila suitablcfsnish hasbeen obtained.
anyq way the end rcstlltdoesnotlook as gtltlJ as using the nlachine cut vcrsions 1:ow evcr It 1acks IittIt 7 if anything in c' tliciency and so can be recolnl mended forthebeginnerorfor anyone who fdels they do notyethave tlle ability to cuta norm alpinion.
W hile I MOM people are quitc capablc 0f Carrying out thkt work required to m zke a Pinion- thore artl som e who m ay feelthe task solllew hatdaunting.
thetubeisdesignedto fit013thearbor of the w heel w ith which it associated, and instead of teeth a series of rods connect thd disks to
Th0 pinion consistsoftwobrassdisks
with a tube in the centrc thatjoins them' 'V01CVêt1$ kllo5&n aSa bobbin.
lnthatcaseitisworthuq hiletryingtt) cach other, the drawing and m ake a lantcrn pinlon-which as the name suggests- looks like a lantern when f ' inished.' Exccpt on replicas of Old clocks,where thc originalswould qtlite possibl y havc llad such a pinion
oO o D oO
Lantern Pinion
photograph w illexplain thesystem far bdter than any words possibly can. Although thc cnds technically are disks,ifnnaking a lalltern pinion itis as wt tll tt) Llst l only ()l 1e disk and to
' TypicalEight LeefPinion
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@ anleter. w' hich in thc stated root di instance is4.2m n' 1.Itcan btlslightly l l er f or t hc s a ke ofconvenience if sm a i s he s . Beca us e of the Iength of onC W
m achine a 1cngth of so1id brass, through square.ltcan be very ditlicull lcaving onc end to just over the to see whcn a dri11 is wanderingdiameter required and putting a step particularly a slmall dril1,w hich w ill on the other.Do notpart (t off from bend. N' Vhen all the holes are the bar at this stage. M ake a disk, completed passthrough eitherlengtlls again oversize,withaholethatwillbe of hardened silver steel or special a good fit for the step on the first blued pivot steelthat is available 1()1' piecc. Solder the disk to the first clock m aterialsuppliers.Betbre doing pieces 'soh solderw illdo tine for this thigputa spotofretaining com potllld sortofwork,butm ake surethe disk is on each.Finally the ends of the pins sqtlare.Replace the bar in the chuck, w illneed to be ground off and thkl and machine the otltside diameter of picce thathasbeen used forchucking the ends of the pinion to size and at ptlrposesalso rem oved, the same setting drillthe centralhole. tisnotpossibletojustpick' This w'illneed to be a good fi ton the Ofcoursei arborand so ensure thatthk)drilltlsed any o1d size of pi11 or an)' isaceuratelygrotlnd,thenjtlslrubthe circum ftlrence that takes onefs falltly cutting edges on a piece 01- em cry and tinish u'ith a pinion thatis going c10th to take the very sharp edge off. to run with the rest of the train,Thu' A lternatively drillthe hole undersize cllartshow s how to find both the Icaithiekness-which equals the diam etcr and tlse a ream erto getitright. of the pin and the pitch circlkl Beforepartingotf,indextheholesand diam eter,whichisneededtoplaeethe either spot thenlor if facilities are pils.Therefore ifwe wantan eightavailable drill then). If drillings the pin pinion for a ntlmber one m odtlle holes can be passed rightthrough to the pitch diam eter circle of the pins w hatwillbeconAe the bottom plate. lf will be 8mm and the pin diam etcr ' not,part ofT and take thc work to the 1.1nzm .Tooth depth has also to btp drilling l' nachine and drill through. considcred and the bobbin thatholds making sure the work is perfectly thepinsm usthavetheslmalldiametec square and that the drill also passes the same as thatshown in the chartas
lantern orany otberpinion forthat m attertherc is no need to use a colld ting iton the arbor. when m oun As we know,whecls and pinions are mounted on arbors and the pivots are machined on the ends ofthese.Care hasbetakento getasquareedgewhcn machining a pivotas any taperm eans
the
there cotlld be a chant?kzof it binding inlheholeinthe fralne.Arborscanbe l made fron) silver steel, or special pivotsteelin an attractivc bltle colour that is already hardened can be bought. This is difïiettlt to m achine and the only way to use it w ithout m achining would be to keep itatits original diam cter. ' J' o prevent it m tw ing throtlgh the holes in the plates,collarswould have tobefitted. ltw illthereforebeaswell,tlnlessone isvcry experieneedsto use silverstcel.
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C hapter 9 - F inishing A wcll-tinished clock m ovement is solnething that can be admired over and over again. Although in gent lral wetend to think'ofpolished brasswork there is : 1grcattlealm()rc to ' linisllillg than thatalond.N o m atterhow nicely polished the wheels and plates m ay be,thtleffectcan be completely ruined by untidy work dlscwherc. A Il polishing work should be carried out with 1 series of progrcssively ïiner polishing meditlms,the typc ofwhicll willdepend on the originalsurface of the m aterial being workcd on. If thc original surface is badl y pitted thell work willhave to startwith various grades of abrasive papers or cloths' , theiruse should be keptto an absolute m inim um as they can creat: m ore problem sthan they solve.N evcruse a piece of abrasive m aterial that has previously been tlsed on steel) on brass, minute particles of steel can becom e em bcdded and cause scratching ofthe surface.
Throughout this book thc need to reduce friction and weight has bettl) stressed alld first thotlghts 01 1 polishi13g m tlst bc ail' nt ltl at this. M achine-cutting lmcthods invariably Ieavk)l uetalragged alld uneven and no l matter ho' w careful one is or how sharp the tools.to gcttlle bestfrolu a clock.extra wkll'k is nt ledk ld to rtln-tove these blcm ishcs.Thislneanstrying to s11-100th the etlgkls of the teeth on al1 wheels inclLlding the escapelnentalld p()lishing other w' orking surfaces. Obviously'when itcolnes to the ted h of u' heel$ 1 a lot of care needg to be takcn to ensurc they do notloosd their profile and so a piece of suitably shapcd wootl can be used i13
conjunctionwithapolishingl' neditlnR, taking careto keep thewoodatnindty degrees to the sides of the wheclse escapem ent wheels in partictllarnced attention and it m ay again be nceessary to make a suitably shaped piece ofwood to getthc bestrcsults.
Before work starts on polishing for appearance itisnecessary to carry out polishing to im prove the working of Pivots the m ovem ent and only then can the Pivotsand the holes in whiclzthtty are question ofappearancebcconsidered. to run need attentions although the 92
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@ holes reall y should have been dealt el-nery cloth or paper to give it :1 w ith when they were madc,to ensure thcre was a good running fit witllthe pivot. Special finishing broaches are available for the purpose but anyone not w anting to invest in these can easily m ake a suitabletoolfrom siIver steel. M achine a short length to thc same taperasthebroach thatwasused to m ake the hole and file the taper to halfthediam eterinthesam eway that one m akes a d-bit.Rem ove any burrs from the edges,harden and tem perto
a dark straw colourand then justrun the llatsurface on a picce ofvery line
suitable edgc.This willprovide a nik ?e polish to thc holcs,butdo rul melubel. to keep itsquare when itis used. The actualbearing surfaceofthepivtlt should be polished to as high : 1linisll as possible. Special files can be boughtfor so doing,w ith an edge at an angle which prevents destroying the square edge.As usualthere is l 1k) need to investin such a toolasourold friend a piece of hardwood dan be presscd into service. lf the hnish on the pivot is very bad stick on somc
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very fine em tlry papt )r as a start and use that, hnislling as usual with a polishing lucdium , The biggest problem when polishing pivots is supporting thena and the best device
for the purpose is ajaeottool. (See
Nvoodcn dtnvelin the tailstock chucks fronl lhe headstock, drill a hole thc diam etcr of the pis' ot to be polishedcutthe dowelso thatonly halftht lhole dianleter is leftand the piqotq'iIlrest in thatwhile itis being polishdd.
photos on pages 94-99 alld draw ings
on pages l()2 & l03)Consisting ofa tailstock supportofsom esort,eithera taper or bar that can be held in a chuek, a bloek is m ade that drops below centreheightandfittcdto thatis a drum madc of brass or plastic that has a series of grooves in the cdge. These start life as holes and then are m achined to halfthpirdiameterso thal when theblock isrotated a groove can be setin a position to stlpporta pivot. lt is an easy toolto make and well worth the eflbrt.Howeverthere isan alternative and thatisto puta piece of 98
C rossing O ut This is the horologist's term for reducing thd weight of w' heels by removing areas frolu the centrelcaving a spoked effccts which can also Iook attractive.Tht?shapd oftlle spokcs is a m atter of pergonalchoicc butthey should becrossedoutinstlch 11Nvay thatnice square edges are lt lh and when polislzing is carried out those edges are m aintained. M ost 01the work can be done q'ith good quality ncedlc files,stressing the need 99
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to buy quality fi1es rather thall cheap ones. It is far better to buy threc o1 ' four good ones, rather thal)a ' wallet containing num erous cheap ones,the shapes of nlany of which woultlbc unsuitable ltnyway. It is possible to buy escapel n ent files w hich are specially naatle ft ar this sort tlf ' Iine work and inclttde specialshapds.The
atlthor has naade a h111alI fi1ing m achinc thatis particulal y usefulfor crossing outas its usc tllhsures thattlle edgcs rel -nain square wi lh the work supported atninety degrtcsto the ' hle. Detailsofconstruction ofthe l' nachine al v given in the Nvorkhllop Practice Series Book 11um bcr 3 1 :Useftl1 W tlrksllop Tools'.
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@ Pallets Obviotlsly it ig nict ? to polish tlle visible surfaee of the pallets to l ' nake thel m lookgoottbutl' nostilmportantof a11isthc necdto im partagood finish to the working stlrfaces so they w ill l m ate snlootllly w ith the teeth of the tscape whkltll. lt is gcnerê tIly recolnlnended thatthisbedonewitha whcelrotating in the Iathe, w'lile thc palIets are stlpported on a hand tool rest.The polishing wheel is lmadc of wood and by supporting thc palIet011 the rest the working stlrfaces capl be contoured w' hile rem aining square to thcsides.
Lay tl' lc plates on a llat stlrface t' ol' polishing the sidt ls antl tlse 11 blotzk' with 1$ Iarge surface area to do the work. Det'p m arks can btt rennoved w ith an abrasivc paper, Thc type known as wet-and-dry is very good. Use the fillest grade and B' dt it thoroughly washing the residue off underarunlping tap. On finescratches, usc a pit lee of card stuck to thtl polishing btock and soaked in 81 polishing m ediunlsuch as Brasso ora silmilar col nlnercial product. Ensure when the plate is turned overthatthe supporting surface is thorotlghiy cical) and degreased before starting on thd second side. It is very easy, when polishing thc flatstlrfacesofthe platcs
to allow thtlabrasiN' cl ' naterialto tr ktustp a rotlnding off of thc edgds. Tllis should be asr oidcd ata11costs' ,ifspacc Perl m its use a large piece of trard soaked in the polishing m tdiunn and lajd on a llat surface and work the plateon that,ratlerthan theotherukty round. U se a figtlre-of-k?jght m oveluent' -1he ' finishcd restlltshould
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they t' y:llldo tlsthpup1 -k 7job.pklrtit-t!larly asin luostcasesthe lastthing thatNvill be w anted ' w illbe sharp edges.
rbors
The nlalerials to be used l ' br nlakiI1g notbe grained in any way buljusl arbors has already been covtlretland have a highly polished surfaee. for l nost pcop1t, this l ' neans siIver Polishing mops have their purposes stcel.w' llic11 generally colues w'itl) an but generaIly their usk l results in already lint lly ground surfacc. Tllis rounded edges- w hich m tlst be fi1ish call often be dannêtgk ld i1) :1 avoided. variety of Nvays: tbr exal nplt? 11)ttrks W ral) thklplates in clean c(oth svhiIc a' wr aiting rc-asscl ubly.
Plates Firstthoughtsarethathnishillg plates is col uparativel y sinlple task hut therearecertainthingsthat' w' cnecdto look outfor.Al1too often a clock is spoilt by filklm arks along the plate edg.esandcareshouldbetaken tllatalI these are rtlllloved by draw filillg, while atthd sallle tinae ensuring thktt the tldgt ?sare atninety degrcesand are keptsquartl,Clam p theplatesbetween lcngthsofangle to work on the edges, keeping theangleascloseto theplate edgesaspossible,protcctingthe sides ofthe platesby ptttting paperbetw' dell them and thc angle beforc tighlcning tlp. Finish lhut edges with a very Gnu' abrasivc c10th wrapped tightly rotlnd a filesfollowtd by a rub w ith apittceof sqtlare-cdged hardwood with a Iiberal am otlntofablusspoIishersprcad on it.
polishi1' 1g 11' tf . )p k)1, 1flatareasisl' lk'ttk)be l' econAl' nclltltltli11ti' le case ()ftl ' le $' 1iIlal' s
Pillars PiIlal-sandl' hescleïvs-ifany.llnathol(1 theln necd partieular attention.lf the pillars ar: plain tlere u'ikl be no probldm as they can be initially polished while rotating in the Iathe. Finighing work shouldalwaysbeklolle along thcir Iength; no matter how carefully lhe work is done. wilness m arks invariably w i1lrem ain on work done in the lathe.Ifthe pillars have been shaped we are faced w ith different problcm s as m achining m arksareinevitableandthcsemustbe rem oved. Frequently tiny chatter m arks are Iikely to be lcfl in any recesses thal have been made and initially thesew illhaveto beremoved with an abrasive paper while thcy are in the Iathe.A lthough the tlsu of a
frol ' u cl1(lt-k jaw' s are a k-oI2)Int'n problelm and are otïen eatlsetlby thkl w ork catching and rel' naining stationary Brhilc the lathklcontintlesto rcvolve.restllting in eithcrscorillg or distloltltlratl 'ollofthc l' netal.11iseasy to say.''Nlak'e stlreitdoesnotcatch in that fashiol7'-butitis l -nuch harcler tk) acttlally preventitfrom so doing.lfit docshappcn the l' narkswillhavc to be erased by polishing and therd are severalschoolsofthoughton htlh'this should be done. Thc most poptllal' m ethod is to use em ory cloth or 2, sil -niIar abrasive while the work is revolvillg' .asw ith the pillars itisvcry hard to disguise the polishing operation donein thisway and a ' finc finish can be obtaincd by working lengthways. O ncc m ores a range of polislling m aterial should bc tlçtttt becom ing progressively tiner as îhe
fsnish improves. Here too is a job where :1polishing m op can do a f irst-
classjob.Tllestepthatismachilledto 105
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@ while thtp wlleel is held firtnly in
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m ake the pivotshould be treated with extra care.Firstly the step mustbe at ninety degrecs as,if it is atan angle, there is always a slight chance of it m oving into the pivot holes and creating unwantcd triction.ltfollow s therefore thatwe do notreally wantto
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roundtheedgesofthestep-overwhen smooth and highly polished butgetit polishing and one way to avoid thisit in abrightlightandparticularlyifthat
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lf possible look atitin
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d aylight,whichisfarsuperiortoany artificiallightthatisavailable.
s'Iaterials Itcannotbe stressed too much that coarseabrasivec10th orpapershould never be used and we should think
Som e peoplc like to see blue arbors
only in tel -ms of l ine and extra sne m aterials.W here there are deep m arks it is better to rem ove them with a a Sw iss precision tiIe' , these are . available in a num ber ot grades and generally speaking Grade () will be
suppliersofclock parts can supply the nccessary chem icalsto blue the steel. ltis a simple process and the finished resultcan look very good btltin order to getthe rightresultthe steelm ustbe highly polished in the first place.
cause nlore PrOblems than they Nvi1l ratherthan aquickfix to savea 1otof rem ove. ln the long run it w ill be polishing work.
found cheaperto buy one good lile tlasthalf a dozen cheap that willotl
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There are m any proprietary m aterials available txor imparting a very high finish and they can be botlghtthrough ood suppliers of horological # m aterials.m ost willdo a farsuperior
A normal engineering m ethod of holdingwheelsforworkingon thetlat surf.acewould be to putpinsin a piece of wood, adiacent to the edges, to prevcnt the . work m oving w ith the
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ability to kt lep tim e and its overall appearance,that latter only achievcd byhardworkanddedicationbutinthe long run is wellworthwhile.
G rade4asthemarksredtlceindepth. blemishesandmustberegardedasa Never use cheap files as they w ill m eans of enhancing appearances
ones.
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A clock is judged on two things:its
s and apart om using special blue pivotsteel, there are other ways to achievethis.Mostmodclengineering suppliers. all gunsmiths and somc
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cndsothatemerypaper.etcwillnot o nceseemedtobeperfectcanlook badly scored
tendtotipovertheedgcasitismoved
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light is angled to the surface, what
position, nlaterial ean be saved by using the sal' ne piece ofwood for all the w heels and l' naking the recess gradually largerasthewheclsincrease in size.
needed for deep marks,moving to Chemical blueing will not rcmove
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out thoroughly it w ill never be to a high standard.Don'tbeafraidto tlsea magnifying glass to exam ine the linish.Frequentl y looking ata partin an indifferentlightw illm ake itappear
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are used a pcrfectfinish requires a 1ot
ofhard work and unless itis carried
purposes-as the edges ofthe wheels are likely atleastto be m arked vcry badly and at the worst irreparably dam aged.Attempting to remove such m arks would change entirely the shape ofthe wheeland so under no circumstances should the mdhod be resorted to.It is far better to cut a sm allrecess in a piece ofwoodsin which the wheel w i1l fit w ithout m oving around and w ith the edges proud of the lip. This allows tbe polishing m edium to be kept tlat,
n ofthcpolishing j toan ythNo ingmthaatt n betpmuracth aisal ed cetio ucochkm met hong ds eo Ib scwhe re. tec ra wha er s a ar rather too drastic fors cl aki .
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C hapter 10 F aces, H ands and C ases Having goneto a grcatdealoftrouble to l' naktpa c1oek 1hcn i1isbeholden 01 1 thebuilderto titan attractive face to it and there ark ?nllmerotls ideas thalcktn be used for s0 dolng. Befoi 'kl discussing tllesd wtl should Iook at how tlle fat le wilI bd fitted to thc l' novclnent. In its bttsic form atker having been collnpletcd the frontface
of the movenlent w ill consist of a plate.with four screvvs orbolts atthtl cornersand a nulmberofholesthrotlgh Nvhich are sticking pieces ofstcel(l11c pivots)thatgo rotlndwhen tlklkrlotzk is w orking.Itisnotatthisstage thklnlost ' attractive thing to Iook at.Anyuuy it Nvould notbepossibleto tita factl01)it as itstandsand so allotherplate ( 2a1Ied
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Thcre are hundreds of com m ercially m ade faccs in al1 sizes available for thosc who do notw ish to attem ptto m ake their ow n; they range from being very cheap to highly expensive. The expensive onesare worksofartin their Ow n rightand are in m ost Cases quitc intricate in theirdesign.They are m adeofmetaland engraved oretchede not only with the num erals but also w ith various patterns.This is not to say that som e of thk l cheapcr com m ercially-m ade dials arc not attractive and a book like this cannol . possibly offer a description of th: whole wide range.
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frequently of wood,and is quite
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False Plate
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W e are anyway concerned w ith m aking a clock and for m any,if not m ostpeople.thiswillinclude theface. W c should start by separating faces into two parts, the full face antl the chapter ring.The latter consists of a m etalring ofsuitable diam eterprinted w ith hours and probably sub-divided into m inutes.This is hxed to a basc, attractiveparticularly on largerclocks. Thc fullface isexactly whatthcnam c suggests:a com plete printed face as a false plate is puton the front.This one unit. has a large hole in the centre that allows plcnty of clearance for the W hichevertype is chosen the biggest hand colletsand forthe square on the problem w ill be the num erals. W ith end ofthe drum ,w hich is to be used care itispossibl eto engrave Roman for winding. Four pillars keep the numerals with the aid of a milling platc ata suitable distance and short m achine.Itw i11be aswellto firstdraw extensions to these support a further them fu11size on a piece ofpaperand plate, the screw s into this are then decide the bestway to setabout countersunk so they are not it. To form a figure l it w ill be noticeable, it is know n as the front necessary to use a straight line with plate and the face willbe l ixed to it. short cross pieces and in orderto get 11O
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@ bechem icallyblackedforappearance.
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Itisalso possible to buy self-adhesivc plastic numcralsw ith various' l inishes that can be stuck on to alm ost any surface.Transfcrs,which are specially designed for clock faces, are also
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readily available and itis diffictlltto
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tellthem from cngraving.W e are al1
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aware of the wide range of rub-on transfers non'aka 'ilable in stationers
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and most art suppliers stock a
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considerably larger range than the average stationer.These do not look al1 that attractive ' w hen used for nlaking clock faces but if they art? caret' tllIy appliedto brassandthen left
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to soak for twenty-four hours in an ctching solution as purchased at dealers in radio eqtliplnentsthe brass t.ound them w illetch away lea:,ing tlltp figures standing proud. ' W -ithout rem oving the transtkrs,wash the factl these accuratc the graduations on the orring in waterand allow itto dry but table 1111 . 1stbttuorked to.Figtlres X or do not rub it to get it dry. Apply a V wilIneed to be a pairoflines.again chem ical blacking solution to thkl w ith short cross pieces top and met alandwhenithasdoneitsjobarub bottoln' -two sizcs of cutter should be off the transtkrs.The result is black used on thesc figtlres to give an face or ring w ith bright brass inlproved appcarance.On slnallclock numbers.Be careftllhow the transfers facesnormall' nilIing cuttersare Iikely are rubbed off as the etclling is not to be too Iarge and dentalburrscan be N'ery deep and ifthey are attacked with used instead.A pointofinterestisthat emery paptlr thtl num bers wi11 bc a clock nevershowsthe tigure lV:four rubbed rightaway. is alw ays shown as IIII.The ' I illished num berscan I nkrfilled w ith black wax- Readers who havc com puters cal' which show s up weI1 on brass or produce their own designs for cIock altlm inium ,whichever is used forthe faces, which can be printed on thin card and stuck in place.A lternatively face orchapterring. they can be printed on a transf-ersheet It is possible to buy thi11 brass and this can be used directly on lllost nulnbers thatcan be stuck on to any m aterials. As far as design is nlatcrialand if one w ishes cotlld tirst eoncerned a wide range of options is
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Top Fittings forcase available in a variety ofstyles and si zes
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tje !op ofthe case StlppOrtS
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aIso from hardwood strip,
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rebated and qlazed
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Tjjecase Made from hardwood strip rebated to QCCOM Veneered pI9wood sides.Doorfrom hardw ood strip,rebate and glaze. Shape ofdoortop i s
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opti()na1.Fi tpi8nOhin9esand r e C e S S C d r r l dQROtiCCQtChOS. Use comm ercialbeading where
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required.Make plinth of hDrdWood.
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the movement.The dooris
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. ' . .. yjje jjood ' j, I.........a A separate partOfthe CaSe W hich is screwed ' ' in place.M ake from . , : : hardwood strip, rebate : . :. i (j . 1 . : a n d s e t n v e n e e r e : : r)I9wood.A board across
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t hema erialfrom whicht yareto C ases jot , t xhe
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Ue m aue. they arc then fretted otlt using a piercing saw antlnt zedle filt ps. The lixing Willdepend on the design ojxa jjarticular clock and it m ay, Or
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. v,, ,. ,lle lnaklng Ofa CI ISC Calls generally dj jkwjat sut oj-skil1s as in the tor a jj main tjC WOrk w jjj be w ith wood. There are exceptjons,skejeton clocks
. and it iS dotlbtftll Whether m any jxjyjjyjjjyjj jjom (;aj. y $1 tyjyt;m j;ajjy ()COj3jo woujjj w jyjj jo jut;kjjy yuq yjj a 1)12tCkCd, OF blLled if One nriSh(ts; task. som etim es a clock w il1 be alternatively itcould be painted.Once djspjaycd în aglasscasc them aking of
sjges avai)ablt 7I:OY Y CFCIf 11ly althotlgh . tjju j ugtjj()U t)t JIXi!)g m ay jjgty' d to $0
youtthc task;onc ofthe easiestis gO ê 1 jo (;rtj(;r jjjo gjayjj jyom tj qt; j(;(;aj
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available if a computer is used. lland: iI
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Anyone w ho has com plcted a m ovcm ent would bc advised to take their tillle when considering the face
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Hands can be cutfrom thin brass or
steel,onceagainthe lessweightthey
have the better.There is a w ide rans ze and in fat ytitisagood ideato draw ofm ore or less standard designs and one ()n paper,w ith or withoutthe aid i n addition there is no reason why ofa com ptlterand stltittem porariIy in p placo.A day or1wo iatklrdraw another ersonal ideas cannot bc used. For exannple they could renccta hobby or one and sec ho' w that Iooks, keep otherinterestorpcrhapssom ethingdo tlxperirnenting untiI a good idea of 'svith the f. fniIy,/$11thesd things give how the tinished articltt w'ill look is individuala ity to a clock and m akt l it obtained. personal. It is as well to draw them hrstofa1lon paper,which isstuck on -
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J'//t tz .s .ll. k(.,//?/.st/,. c.t.'tt.vil)'vd -/kt,F.c,//?t/t?,?a t.t????/?lI/t:,:Theb't..t/n çpt. tli(.,i./?c t. .' . P'' l'''é-( lt ?'' (' t ï 1'. ( 1t '??d@ . î' ?l?t . ' /f l'lp?/c't' c o'-/?'' /?Jl?e' t' fF tz. $ 'tl' (ln. b m h-'. h' . E;;îI)ç,lIl ' ,b . ;1n: c,tlt, à .,. t7??/)t?adtied ( . /'tsvln.ted.xos,thv,Jj, #p/ . v?7(. ( ?.in , . ,0''':/t?1. ,w?-t/.& // ?t-centre '$'/?//tI)(. zvilI()n (? I //,/ . -''ltl nbertlls./?t?/à?r . ?, ' ,.1. 4i. ttf,t . ( . b .g/ y) y. jg/y/. - .,,s,,vttîàvttvb, .
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be polished.TI1istlan be I 1eld togttther using a tIcarsi1icone and uotlzing else and looks attractive as there is 110 wooden beading to obscure the vic' w of the clock.The base on which the case stands should be of hardwood and havtt a groove cut in it for the glasscase to slip into. The l ' nore traditional glass case consists of thin wooden beading with the glass Iet into it. Again hardwood should bk ltlsed and the gl -ooN' tlforthc glass can be made with a nlilling eutter if a router is notaxqailable.The
corncrjointscanbenaitrcdtoinaprove yl vnchpolished.(lnceagain thcbcst appearancc, oncc agai1 it is w,ol-th advice is to contact advcrtiscrs in
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haN'ing thc t ldgt?softhk lglasspolished betore t' nak'illg the case.
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(leneraIly speaking ' we think i1 l more traditiona1 terlms Nvhcn considering c iascsandthtlchoiceofsvoodbeconles nlportant.ldealIy the case should be lmade of hardvvood planks btlt these are gettil1g lnord and l uore dit-ficultto obtaill. For long castl clockh i sol nkl scctions ctluld bt ' tl' nade ot- veneerkld blockboard but the problclm ojobtaining suitable m aterials is beconning N'klry diflicult indced. ()11kl ansurer is to tlse hartlwood strips and fit a good qtlality vtpllccred p1y in nlachinedgrooves;itishard tt)teI1the finishkld result frolm solid wood. It
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should btp possiblkl to get stlitable lnalel-ialsto t' nake sl-nal1ercIock cases from ()nt7ofthe tilnbcrlmerchants that dcal in hardwoods although it l' nay nlcau dealing w ith a colnpany solme distancdfroln ' whereouelivesasthere arc not lllany ofthzm Ieftthese days. Infoj-nlation on wllere to (lbtain wood ca11 be obtained frol' n the advertiselnents in l' nagazines dealing with woodworking orclocks. û' ases cal)bc ' hnishkld vvitl)one ofthe nlodern varnishes althotlgl l traditionally they llaN' e alvvays btpen
spccia1ist llaagazines for help and infonnation before deciding thc best svav to $ . :t)abotlt it.It is bestto avoitl 'ores w,j D I5- s' t aeI1 tj)înking ojnaaterjajs. thcir stock' is ailmcd at a Inass l markut ant. t tor a differcnt pul.pose an(jis unlikcly to bc stlitable jbrthissortofwork. .
slany cloek cascs arc tinished with f-ancy. shaped beading and ornalments Nvhich can be obtaincd frol m supplicrs Of clocklnaking equiplllent,althotlgh l ' nostly wood som e of thcse Cnlbellishl ' nents are brass and either B' êl)'tldy do add tlle tinishing totlches to 11tlltàok case.
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Y' OI-ITIUIZS Goil1g Trai11fornlula for trhtrcking correct' vvhklk llarrangelnu'ntand forfinding lellgtllofposverchol' ttrequircd. N ().oftccth in centrk lw' ht lelx N o.t3ftoeth i113rd U llt ?e1 64 x 6() oj= ($() N o. 0ftceth in 3rd pinion x No.ofteeth il' lestlaptlNvhkltllpinion 8x 8 A Sthe celltle 411001pinion has eighttkltlth and the groat&N' 1 l001ninoty-six,the NN'I'CCIrotates: 96 8 = 12 hours
JXl' 1CIiftho dialmctklrOfthebarl-elis2 inohkrs,th0col o h'i11beunnmund. 7:x 2 = 6.ajykj ak yjaj ;sij atht ?sam cpcriod.Asthecord isdotlble.the wvightfalls tlll.t'ugja011jy yjajj-tjak?distance thatitunNvindsfrom the barrele 'ic,3.14 inchds in tNs,e!N, k2jaoursorj 'ustover6andaquartdrinchesevdry fulIday oftwentyThatis-thecquivalcntoffourfeetantlt' wo inchdsineightdays' . tourjjouys,' j u'hich is abotltt' lk ll maxinaunathatnlostpeople are likcly t()w'antitto un' w ind. jtal m ountsto abouth ;ixtcen turnsround t)' le Nvj)k)t?Iand so therc should be abotlt scvunteen coiIson the drtllm. .
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C hord Tables To dikide a cirt zlt linto even sections.tlse thctable below.The figurcsgiqren are fora dialmeterofone.To fintlrequilvd figtlre-l uultiply Iength 01-k2Ilord forthe numberofspaceswanted by diam etcrofcircleto bedivided. Num ber ofSpaces
Length ofChord
Num ber ofSpaces
Length ofC hord
3 4
0.8860 0.7071
36 37
0.0872 0.0848
69 70
0.0455 0.0449
Pendulum s
5
0.5878
38
0. 0826
71
0.0442
The mathem aticalcalculation fortim ing a com plete oscillation ofa sim ple pendulum is:
6 y 8
0.5000 ( . ).4339 0.3827
39 4: 4l
0.0805 (). ()' yj yj 0.0765
72 yj j 7y
0. 0436 :.4 . )4.3: ().( . )4,4
9
0 .3429--()
42
0.0747
75
().0419
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length Tim e - 7: gr avity in feet .
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or t= ! whcre7:=3 14 l59 gravity = 32.l9 .
f c s
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Tocalctllate thktlcngth of:1pcndulum required for: 1given trainofwheelstlltl totalnumberofteeth in the centre,third and cscap: wheels,are multiplicd together and then multiplicd by two.They are then divided by the numberof leavesin thepinionsotthird and escape.m tlltiplicdtogcther . Forexalzzple,Centre Svheel= 64t-Third W heel= 60t-Escape W heel= 30t
Pinionsare1 70th8 leaf.
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12
0.2588
45
0.()698
78
0.0403
l3 l4 jj 16 17 18 19
0.2393 0.2225 ()a()y( ) ()'jgjj . 0.1838 0.1736 0.l646
46 47 4: 49 50 51 52
0.0682 ().0668 (),()(jj4 ( ,.:6, . 4.) aj j 0.()6 (). t)61( 3 ().()6()4
79 80 h yj jya j y? 84 85
0.0398 ().0393 (. ).e?j yj y ().()?j y? () .( )?, yj y ().(). y, yz) 0.0370
2 0 20
0 .1564 0
3090 ().2817 .
.
I I
I2. I .
() = 60 beats perm inute 6
II I It I ;
3604)beats per hour
.
36():
I
1g I
=
122
43 44
:.073() 0.0713
.
76 77
0.04I. 7 0.0408
53
0.0592
86
0.0365
J,Z g..,.J
1590 ().ju : ):3 ().j?()a
54 . ' F. 5 j(j
0.058l (. ),4). , 57j ().4)56j
87 :8 j. 49
0.036l ( . ).(). 357 ().()?j?
24
0.l305
57
0.055l
90
0.0349
25 26 27 28 29 30 3I 32 33
0.l253 0.l205 0.116l 0.l120 ().l081 0.1081 0.l012 0.0980 0.0951
58 59 60 6I 62 62 64 65 66
0.0541 ().()532 ().0523 0.05 15 0.0507 0.()507 ().0491 0.0483 0.0476
91 C)2 93 94 95 96 97 98 99
0.0345 0.034 I 0.0338 0.0334 0.0331 0.033l 0.0324 0.0321 0.0317
34 5
0 . 0 923 0. 0896
6 7 68
0 . 0 469 100 0. 0314 0. 0462
.
64 x 60 x 3()x 2 8x 8
N um ber Length ofSpaces ofC hord
.
.
123
k.
'j'. .. c . , .'..). .. t
k ; ... Ltt. j$ '. k.. jjj$y
C om m on C lock Trains 1:
.
C-entrc 31-( 1 ' q/heel Pinioll
I
3rd Nvheel
ûScapt y tscape Vibralions Pinion N' Vhtrtll pt lr nlintlte
Length of Pendulul ' n
l12 t ?6
14 12
1()5 9()
14 I2
60 3()
6() 6()
39.l4'' 3t?.I4''
' !I r
80 64 75
l0 8 h4
75 6() 6()
10 8 8
30 3t) 32
60 6( ) 75
39.14'' 39 14'' 25.53''
''
80 1()8
8 12
72 1()()
8 1()
3() 32
t ?() 96
17.39 !5.28
j'
I I
II iI
ti I.
i I
r
/' );1
.
pII ,
124
