Model Engineer 20 Page Preview issue 4725

PublishedbyMortonsMediaGroupLtd, MediaCentre,MortonWay,Horncastle,LincsLN96JR Tel:01507529589Fax:01507371066

©2023MortonsMediaISSN0026-7325

www.model-engineer.co.uk

EDITORIAL

Editor: MartinR.Evans

Deputyeditor: DianeCarney

Designer: DruckMediaPvt.Ltd.

ClubNews: GeoffTheasby

Illustrator: GrahameChambers

Publisher: SteveO’Hara

CUSTOMERSERVICES

GeneralQueriesandBackIssues

01507529529Monday-Friday:8.30am-5pm Answerphone24hr help@classicmagazines.co.uk www.classicmagazines.co.uk

ADVERTISING

Groupadvertisingmanager: SueKeily

Advertising: CraigAmess camess@mortons.co.ukTel:01507529537

Adproduction: AndyTompkins

Bypost: ModelEngineeradvertising,MortonsMedia Group,MediaCentre,MortonWay, Horncastle,LincsLN96JR

PUBLISHING

Salesanddistributionmanager: CarlSmith

Marketingmanager: CharlottePark

Commercialdirector: NigelHole

Publishingdirector: DanSavage

SUBSCRIPTION

Fullsubscriptionrates(butseepage366foroffer): (12months,26issues,incpostandpacking)–UK£128.70.Exportratesarealsoavailable, UKsubscriptionsarezero-ratedforthepurposes ofValueAddedTax.

Enquiries:subscriptions@mortons.co.uk

PRINTANDDISTRIBUTIONS

Printedby: WilliamGibbons&Son,26Planetary Road,Willenhall,WestMidlands,WV133XB

Distributionby: SeymourDistributionLimited, 2EastPoultryAvenue,LondonEC1A9PT

EDITORIALCONTRIBUTION

Acceptedphotographsandarticleswillbepaidfor uponpublication.Itemswecannotusewillbereturned ifaccompaniedbyastampedaddressedenvelope andrecordeddeliverymustclearlystatesoand enclosesufficientpostage.Incommonwithpractice onotherperiodicals,allmaterialissentorreturnedat thecontributor’sownriskandneitherModelEngineer, theeditor,thestaffnorMortonsMediaLtdcanbe heldresponsibleforlossordamage,howsoever caused.TheopinionsexpressedinModelEngineer arenotnecessarilythoseoftheeditororstaff.This periodicalmustnot,withoutthewrittenconsentofthe publishersfirstbeinggiven,belent,sold,hiredoutor otherwisedisposedofinamutilatedconditionorin otherunauthorisedcoverbywayoftradeorannexed tooraspartofanypublicationoradvertising,literary orpictorialmannerwhatsoever.

Vol.231No.47258–21September2023

368SMOKERINGS

News,viewsandcommentontheworldof modelengineering.

369RADIALVALVEGEARSAGAIN

DuncanWebsterexploresthesubtletiesof valvegearoperation.

374AFIVE-INCHGAUGE0-4-0 PADARNRAILWAYTENDER LOCOMOTIVE

Luker presents FireQueen,aWelshslate quarrylocomotive.

378IMLEC2023

RobSpeareobservesthesecondday’s runningatAshtonCourtinBristol.

382THEEATINGOFELEPHANTS

SteveGoodbodyarguesthatanythingis possibleifyoutakeitabiteatatime.

386WEVISITTHEWIGANAND DISTRICTSOCIETYOF MODELENGINEERS

JohnArrowsmithvisitsatrackinthenorth withapleasantwoodlandsetting.

389RECYCLINGA3½ INCH GAUGESOUTHERNSCHOOLS LOCOMOTIVE

RobertHobbsturnsaboxofbitsintothe Southern’s‘V’Classlocomotive Winchester

394ADIRTYTRAM–ABITOF NOSTALGIA

AshleyBestcreatesaBoltontrammodelas itreallywas–dirtyandunkempt.

400THESTATIONARYSTEAM ENGINE

RonFitzgeraldtellsthestoryofthe developmentofthestationarysteamengine.

405BOOKREVIEWS

BrianBakerreviewsthetwolatestbooksfrom BrianandIanReading.

406THELATHEELECTRONIC LEADSCREW

PeterRussellmakesscrewcuttingeasywitha computerdrivenleadscrew.

408LNERB1LOCOMOTIVE

DougHewsonpresentsatruetoscalefive-inch gaugemodelofThompson’sB1.

412CLUBNEWS

GeoffTheasbycompilesthelatestfrommodel engineeringclubsaroundtheworld.

415CLUBDIARY FutureEvents.

http://www.facebook.com/modelengineersworkshop

http://twitter.com/

MidlandsHighlights

TheMidlandsModel EngineeringExhibitionwill berunningthisyearona fullheadofsteam.The SocietyofModeland ExperimentalEngineers (SMEE)and Model Engineer willbetherein force,celebratingtheir joint125thanniversary, andtheSMEEworkshop willonceagainbein fulloperation,including demonstrationsbyNeil Wyatt, ModelEngineers Workshop editor,of3D printing.TheSMEEstandwill alsofeaturealargecollection ofmodelsfromacrossits history.Thelecturesare backtoo,includingRoger Backhouseon‘UncleJim’ CrebbinandBobReeveon thebehaviourofmetals,and theGasTurbineBuilders Associationwillbeoutside makingalotofnoise.Toround italloffwillbe,asusual,The FosseLiveSteamers.

Aparticularattractionwillbe JohnWilks’snewlycompleted 10¼ inchgaugeLNERP2 Cock O’TheNorth whichwillbe ondisplayattheexhibition. Johnwasaprolificlocomotive builderandsadlypassed awayinNovember2022. Thisisthelastoffivefully workingexhibitionstandard scalesteamlocomotiveshe completedduringhislifetime since1963.Thelocomotive isbuiltentirelyfromworks drawingsandoriginalresearch andreflectsGresley’smost advancedExpresspassenger 2-8-2withLentzpoppet valvegear,Kylchapexhaust andACFIFeedwaterpump asbuiltinitsuniquesemi

streamlinedformin1934.The three-cylinderlocomotivehas aTIGweldedsteelboilerwith superheatersandisbasedat StaplefordMiniatureRailway.

Ontopofallthisthenearly fortytradestandswillprovide aperfectopportunitytostock upreadyforthoselongwinter workshopevenings.More detailsoftheshow,including alistofthetradeandsociety stands,maybefoundatwww. meridienneexhibitions.co.uk

DirtyTram

InthisissueAshleyBesttakes asmalldeviationfromhis usualpristinetrammodelsand continuestocelebratethetrue Boltontraminallitswonderful grubbiness.Hislatesttram emerges,notpristineasusual fromthetramworks,but battered,bruisedandscuffed fromtheaftermathofWorld WarTwo.Inthisissuehegets onwiththeconstructionofthe trambeforesootandgrimeare applied.

Sadly,alsointhisissue, SteveGoodbodyconsumeshis lastmouthfulofelephantand retirestotakeamuch-deserved break.However,hewillsoonbe backtomuseonmattersboth physicalandmetaphysical,like whythetoastalwayslands buttersidedown.Watchthis space.

CheltenhamandHereford

Irecentlyspentaverypleasant weekendoveronthewestside ofthecountryandwasableto visitboththeCheltenhamand Herefordclubs.Cheltenham arecurrentlybusilyoccupiedin buildinganewclubhouse,which appearstobeapproaching completion.Itcomesasa kindofslot-togetherkit,on thelogcabinprinciple,and alreadylooksverysmart.I shalllookforwardtoseeingit againwhenitiscompleteand Ihopetobeabletoinclude areportfromtheclubindue course.WhilethereIreceived alessononthedynamicsof hovercraft–thesubjectis rathermorecomplexthanone mightimagine.Itinvolvesan understandingoftheworkings ofthegyroscope,whichisnot atallintuitive,andIcanconfirm fromdirectexperiencethatthe mathematicsinvolvedisnot easytogetone’sheadaround!

ItwasgoodtovisitHereford again,onthisoccasionwhile theclubwasbusyofferingtrain ridestoasteadystreamof eagerpassengers.Therewere fiveorsixtrainsinoperation, processingaroundtheclub’s longandwindingrailroad,as wellastheusualteaandcakes intheclubroom.

Youcanfindoutmoreabout theHerefordandCheltenham clubs(respectively)atwww. hmse.co.ukand www.cheltsme.org.uk

DIANE CARNEY Assistant Editor

MARTIN EVANS Editor

JohnWilks’sLNERP2CockO’TheNorth(photocourtesyof MeridienneExhibitions).

ThesceneatabusyHerefordclub(photoJocelynFung).

Meridienneexhibitions.

Herefordclub.

Cheltenhamclub.

RadialValve GearsAgain

HEYWOOD’SGEAR

Chas.Brown’sgear

Continuedfromp.280 M.E.4724August25

Backatthebeginningof part2itwasexplainedthata correctedgearembodiessome formofstraight-linemotion. ChasBrown’s( g40)uses Watt#2asdescribedinpart6 (M.E.4723August11).(Chas. BrownwasborninUxbridge and,afteranapprenticeship atMaudslay’s,hewentto SwitzerlandtosetuptheSwiss LocomotiveandMachine Works(SLM)thatbuiltthe locomotivesfortheSnowdon MountainRailwayandothers.)

Itiseasytovisualisethat aspoint d movestotheright alongitsmythicalstraightline, thecorrectinglink ef pivots aroundpoint f,point e moves downandsopoint g moves downbutbylessandso,ifthe vibratinglever gh hasbeen correctlyproportioned,point h staysontheslideaxisas required.Inthismanifestation

Ihaveshownthedrivebeam connectedtoanextension oftheconrodat d.Itwould workequallywellifconnected directlytothecrankpinbut withthissetupthepinat d only seesasmallangularrotation ratherthanfullrotationatthe crankpin,resultinginlesswear, andslightlysmalleroverall widthas fe canbeinlinewith bc.MrBrowniscreditedwith quiteafewvalvegears.This onewouldworkequallywell withthedrivebeamslideetc. infrontoftheaxle-thisway roundleavesmoreroomfor allthegubbins,hasalarger slideradius(agoodthing!)and iseasiertodraw(averygood thing).Itisdescribedinmore detailbelow.

Designmethodology

Whenthiswasoriginally workedoutIusedtheequation heavymethodasforJoygear,

butmostofitcanbedesigned usingCAD,towhichmost peoplenowhaveaccess.The onlyequationrequiredisto nd thepositionof g along de.This isalmostthesameas nding thelengthofthereturncrankin Hackworthgear(seepart5–M.E.4722July28).

First nd mh/gh from mh/gh =(lap+lead)/ab

Ifwecallthevertical movementof g ‘vert’(total movement2*vert),the outphasemotion(seepart 1)isoutphase=vert* mh/ gh *tan(slide)whereslide istheslideangle,whichcan bere-arrangedtogivevert= outphase/(mh/gh *tan(slide))

Theverticaltravelof d,which I’llcallvert2isvert2= ab *(bc + bd)/bc,anditwillbeseenthat vert=vert2*(de - dg)/de. Re-arrangethistoget de – dg =vert* de /vert2.Toavoidall thisIput dg = de/2

Duncan Webster shedslight onwhatisoftenseenas acomplexsubject.

PART8 – CHAS.BROWN’SAND

Fig40 b

h

m c

p a

Browngearforward.

Asbeforelimitslideto20 degrees.Therestisdonein CAD.

Asshownin g41,setout thethreepositionsof d as thoughitwererunningina straightline- d1 isfrontcentre,

d3 isbackcentreand d2 is halfwaybetween.Decideona reasonablelengthfor de -the onlylocomotiveIknowofthat hasanythinglikethisgear has de =4.5* ab.Position g1 and g3.From g1 and g3 draw

linesat25degreestovertical andwheretheycrossgives theslideaxis j.Fromthis pointstrikeanarcthrough g1 and g3.Nowfrom d2 drawa circleradius dg andwherethis crossesthearc g1-g3 is g2

Nowweneedtoposition e1, e2 and e3 e1 and e3 aresimply de from d1 and d3 onthecentre lineand e2 ispositionedby drawingalinethrough d2 and g2,projectingittotheleftand marking e2 at de from d2.We

Fig42 Chas.Browngeometry.

Fig41

nowhavethreepointsand threepointsde neacircle.The commandonmyCADsystem is‘circle’then‘3’.Thispositions point f.Iftheswingof fe is morethan±45degreesyou mightwanttomake gh slightly longerandtryagain.

Whatweneedtodonow isdetermine mh.Thiscanbe doneontheCADaswell.Draw averticallinethroughtheslide axis,offsetitbylap+leadand projectoneofthe25degree lines.Wheretheselinescross ispoint m.Forthetimebeing, settheslideradiussameasthe valverod pm.

Ihavebuilt(yetanother) computermodelforthisgear. Thiscomputermodeloutputs theriseandfallofthedie block.Iftheyarenotquite equalyoucanadjust fe andthe positionof f andtryagain.Itis bynomeansessentialthat e1 and e2 areonthecentreline, justmytidymind.

Oncethemodelisupand running,youcanthenchange theslideradiustogetthebest results.Thefollowingisbased aroundthedimensionsof River Irt (seelaterinthisepisode).I haveused pn =42.5,and nd thattogetastraightlineat midgearIneedtoreducethe slideradiusto36inches.Idon’t understandthisbutwithouta computermodelI’dneverhave foundit.Foracurvedslide withoutoffsettopjoint,points m and n arethesame.

Resultsareshownin gs42 and 43.Anall-roundreasonable valvegear,itmightbepossible togetevenbetterresultsby netuning fe andofcoursethe positionof f,andbychanging theslideradius.

SnowdonMountain version

Thisisshownin photo2 andschematicallyin g44. Thepistonsdonotdrivethe crankpinsdirectly,theydrivevia themainrocker.Presumably thiswasdonetogetthe cylindershigherofftheground onwhatareverysmallwheeled locomotives.Thismainrocker thentakesthepartoflink fe inthegearshownin g40, andthemaindrivingforceis transmittedfromthebottomof themainrockingbeamtothe crankpinbydrivebeam de.The valvesareinsideadmission andsopoint h isabovepoint m.Thevalvemotionisthen transmittedviathevalverocker tothevalvesmountedontopof thecylinders.Allinall,amost ingeniousarrangementbutno, foronceIhaven’tmodelledit.

Heywood’sgear

ThedownsideofBrown’s gearisthattheslideaxiscan turnoutalongwayabovethe cylinderaxis.Thepioneerof 15inchgaugerailways,the Hon.ArthurPercivalHeywood

Browngearreverse.

Browngear–SnowdonMountainversion.

Fig43

Ralph ontheSnowdonMountainRailway.Asitsnamesuggeststherailwayrunsto thetopofSnowdon,Wales’shighestmountain.Definitelyworthatripbutmakesure theyarerunningsteam(photocourtesyofSnowdonMountainRailway).

Heywood’sgear.

overcamethisproblembythe simpleexpedientofbending thedrivebeam( g45).(Sir ArthurPercivalHeywoodBart. waseducatedatEtonandtook amaster’sdegreeinApplied Sciencein1872.Hemore orlessinventedthe15inch ‘minimumgauge’railwayand builtinhisownworkshopsat least velocomotives.)

Itwillalsobenotedthat heusedastraightslidewith theoffsettopjoint.Onhis earlylocomotivesHeywood usedstraightslidesbuton

Muriel (nowrunningas River Irt ontheRavenglassand EskdaleRailway– photo3)he replacedtheslidewithaScott Russellstraightlinelinkageas describedinpart6.Itmightbe

thoughtthatthismultiplicity ofpinjointswouldgiverise toalotoflostmotionbut RiverIrt seemstoworkvery wellindeed.Itismucheasier toreplaceabushwhenwear occursthantoreworkacurved slideandsoitismorelikelyto happen.Thephotographshows RiverIrt inallherglorybythe coalingstageatRavenglass

Designdifferences

WhendesigningHeywood’s gearwecaneitherpositionthe slideaxisatsomeconvenient pointorcalculateitsuchthat thevalverodishorizontalat topandbottomdeadcentres. Eitherway,in g41justmove

RiverIrt anddetailsofthevalvegear(photocourtesyoftheRavenglassandEskdaleRailway).

Fig45

withanenlargementofthe valvegear.

thevibratingleverdownto whereitiswantedandbend link dge tosuitasshownin g45.Thenrepeattheabove procedurebutwiththebent drivebeam.

ThedimensionsIhavefor RiverIrt donotgiveverygood results,soIhavetweakedit slightlyasdescribedaboveto get gs46 and 47.Notatall bad.Ican’ttrackdownwhy thecalculatedvalueofslide angleformidgearis1degree off–Isuspectitissomething todowithoffsettopjoint.Ido nothavethedimensionsofthe straight-linelinkagereplacing theslide,anditisentirely possiblethatitdescribes acurve,butI’veassumed straight.

That’senoughforthistime, thenextepisodewilldelveinto Sisson’sgear.

RiverIrt reverse.

Fig46

Fig47

RiverIrt forward.

AFive-InchGauge 0-4-0PadarnRailwayTender Locomotive

Thesteamexhausts

Continuedfromp.351

M.E.4724August25

WhenIdecidedtomodelthe majestic FireQueen Iknewthe steamexhaustsweregoingto beaninterestingchallenge.In allhonesty,whenIgottothis pointofthebuildthefearof throwinginthetowelbecause ofthoseinsanecopperpipes wasoneofthosecliffhanger momentswherethebuttocks clenchingwasonlymatched bytheexcitementofgettingit right.Well,Ididgetitright,with onlyonefailure-andifIcando it,anybodycan!

Theoriginalexhaustsneed amentionbeforeImoveonto howImadethemformymodel. Likeagreatnumberofthe ttingstheywereforgedinto shapeandbrazedwiththejoint lineattheback(apparently; Ihaven’tbeenfortunate enoughtoactuallyviewthe prototypeasisthecasewith allmybuilds).Thedesignof theexhaust owpathswas aheadofitstimewithlarge, unrestricted owpathstothe smokebox.Icannotimagine forgingthatlargelumpof copperto ttheoriginal locomotive;itmusthavebeen incrediblytimeconsuming,with theoriginalbuildershavinga setofarmsonthemthatwould makeHerculesthinktwiceina bartussle.

I,ofcourse, nishedmybuild beforeIwrotethisarticleandI againfoundmyselfscratching myheadastohowImade thoseexhausts.Luckilyforme, Itookafewpicturestohelp tellthestoryandtohelpboot upmygreymatterRAM.The steamexhaustdrawingsare lightintermsof tmentand lengthdimensionsbecause

mostofthemwillhaveto changeslightlydependingon howthecylinderswere tted andhowthesmokeboxwas ttedforthecouplingrods. Theinnermandrelsizingis probablymoreimportantfor gettingthe nalshapeofthe taperedsectionandblending thatwiththeloftedcylinder. Beforethehammerisbrought intoservicetheend anges needtobemade.

Partingoffcopperinahome workshopisadauntingtask andItrytoavoiditatallcosts; makingtheround angesfrom copperbarshouldbeleftfor theindustrialguyswith ood cooling.Havingsaidthat,the angescaneasilybemade fromhalf-hardcopperplate, withafewmadeatthesame timebyboltingthemtightly together(photo109).The square angewasmadefrom thesameplate;machined, drilledand ledtosizeona

mildsteelblank.Ifthecopper plateisscrewedtothesteel blankitmakesaconvenient holdingjig.Theblankcanbe grippedinthevice,insteadof thesoftercopper,avoidingany deformationwhenmillingthe centreslot(photo110).

Asasidenote:longbefore mytimestartedinthe workshop,thebuildersofold usedtouseneatparaf nasa cutting uidwhenmachining copper.Overtheyearsthe qualitiesofmosthydrocarbons havechangedandparaf n hasn’tbeenspared,making itunsuitabletouseas-is.I’ve hadgoodsuccesswithamix ofmodernparaf nand10-20% usedspindleoil(fromthelast latheservice)whichseemsto workreallywellasacopper cutting uid.Thisisapplied withapaintbrushtothecopper andthecuttingtooltoprevent thegallingthatresultsin horriblecuts.

Luker builds a veinch gaugemodel ofaWelshslatequarry locomotive.

Machiningafew angesfortheexhausts.

Themainbodyoftheexhaust wasforgedaroundamandrel withtheslenderdiameter 10mmandthetaper at sectionmatchingtheangleof thedrawings(assuminga1mm wallthickness).The atsection shouldbearound6mmthick withtheendofthe10mmbar blendedtomatchtheendplate (photo111).Asuitablepieceof 5/8inch16SWGcanbeheated toredhotandquenchedto softenforalittlepanelbeating. Theloftedsectionisforged andthestraightsectionneeds tobeslitandclosedaround the10mmbar.TheLHandRH atsectionareformedslightly differentlytomatchtheswept directionfromthecylindersto thesmokebox,butthesame innerformerscanbeused.The largeendwasthentrimmed toatight tinsidethesquare angeandthen ttedtothe assemblytomeasureoutthe correctpositionofthebend

intothesmokebox.Atthe bendtheforgingwascutat45 degreesandTIGweldedwith theshortsection ippedtoface thesmokebox.Aroundpiece of10mmbarwasinserted intotheshortsectionandthe outsidewasforgedagainstthis bartoasmoothbendbefore lingtoaperfectforgeryofa tightly-bentsection.

Forweldingcopperofthis natureIusenormalsinglecore householdwiring,cleanedwith neemerypapertoremove anycoating.Thismaysound alittleoddwithmanywelders arguingthatitisnotthesame aspropercopper llerrods. Theyareofcoursecorrect-it’s betterandcheaper!

Finally,thethreepiecesof theexhaustpuzzleare tted totheassemblytocheckthat everythingisagood tandthe owpathsarenotconstricted ateitherend(photo112).A barslippedfromtheinsideof

thesmokeboxintotheexhaust steampipeshould twith littleeffort.Imadeapointof

makingthe angesatight t tomakesuretheystayput whenmovingtheexhaustfrom theworkshoptothebrazing hearth.Luckily,thelotstayed putlongenoughforthesilver soldertorunneatly–which, incidentally,matchedthe prototypeperfectly.That nal heatingoperationnaturally annealsthecopper,givingthe slightestamountofleeway whencoaxingthesoldered assemblyto tperfectly.

Theholesforthesmokebox angecannowbedrilledon theassembly,usingapunch guideforcorrectplacement, especiallytheholesclosestto theexhaustbody(photo113). Thedrawingscallforsixbolt holeslikethelargescale,but formymodelIused veholes.

TheinnerformingmandrelandtheLHandRHexhaustbodies.Thebodieshave differentbendsfortheleftandrightsides.Thesplitformercanbeusedforboth withthebendatthesplit.

Fittingthe angesontheassemblyandcheckingtheinternal owpathisnotconstrictedoneitherendwithinternalbars.

Punchingguideforthe angeholestomakesurethenutsdon’tfoulthemainbody. Thetwobackholesweredonefirstandtheremaindermarkedoutforequalspacing usingapairofdividers.

Machiningthecentreslotforthesquare ange,boltedtoamildsteelblankthat wasusedasadrillingjigandfilingguide.

Twoweredrilledasclose aspracticaltotheback,just missingthebend,withthe remainingthreemarkedout withapairofdividers.

Whilewe’reatthatsideof thelocomotive,it’sagoodtime totackletheinsidesmokebox pipingwhichusesthesame angesastheoutside.

Fig23

Thesmokeboxplumbing

Thepipinginsidethesmall smokebox(photo114)issnug butthere’senoughspacefor spannersand ngerstohold screws,etc.Theinside anges areidenticaltotheoutsideand thescrewholescanbespotted withaholdingboltthroughthe smokeboxshell.Ipersonally

silversolderedthe angesin placebutthedrawingsshow thepipeextendingthrough the angewiththeends bell-mouthed,whichismuch easiertomakeandassemble. Ithinkthiswouldbealittle more exibleandwouldseal justaswellasafullysoldered connection.Boththeinside

andoutside angeswillneed tobesealedwithRTVsilicone on nalassemblytoprevent airingressintothesmokebox. Theinside angescrewholes canbecountersunkwithM2 countersunkstainlesssteel screws ttedfromtheinside asstuds(photo115).These makeassemblyeasierwitha little ngerpressureonthetop ofthecountersinkenoughto tightenthenutontheoutside assembly.

Thechimney

Thechimneyforthelargescale modelwasarolledandriveted constructionwithabeautiful coppercap,alsosmithied,at thetop.Thenicethingwitha modellikethisisthechimney islongenoughnottorequire apetticoatand,withcorrect designoftheinnerchimneyand smokeboxdimensions,you’ll endupwithadecentsteamer. ForthemodelImadethe bottomsectionofthechimney fromaluminium.Thiswasreally justforcastingconvenience; thedaythechimneywascast

Smokebox,chimneyandplumbing.

Theblastnozzlestandandsteamexhaustpipeslitupinsidethesmokebox.

MainBody ForgedfromØ5/816SWGcopperpipe Smokeboxendfitting:SilversolderedCUdisk Cylinderflange:SilversolderedCU

Ialsocastanumberofcast ironcomponents.There’sno issuewithcastingaluminium inthesamepotascastiron; thealuminiumactsasadegasserforthecastironand justreportstotheslag.Icould havecastitincastironbutthat meantalongerdayinfrontof thefurnaceandmoremessin theworkshop.

Themachiningrequires littledescriptionandother thanastoutboringbarto preventchatterit’savery

simplecomponenttomachine (photo116).Theseatingfor thecoppercapissimpleto machinewiththechimney pushedontoataperedmandrel andasmallplugfortheother endwithacentreholetokeep everythingsteady(photo117). Thecoppercapisontheother endof‘nottoodif cult’!

Mostfoundriesarereluctant tomeltandcastcopper.There areafewreasonsforthis butthebiggestproblemis blowholesinthe nalcasting,

normallymisdiagnosed.The meltingpointsofcopper oxidesandcoppermetalare veryclose.Thisresultsinthe oxidesmixinginwiththebase metalcopper,onlytocome outofsolution(asgas)when pouredintothemould.Melting largerchunksofcleancopper helpsbutyouwouldstillneed topreventgaspick-upinthe crucible.Intypicalback-yard foundrystyleasuitabledegassingandcappingmixwas devised,usingrawmaterials fromthelocalgrocerand gardenshop.Thecoppercaps cameoutbeautifullywith notablowholefoundduring machining.

Ofcourseonceyou’vecast thecopper,thenextchallenge ismachiningit,whichisjust horrible.Itisgooey(that’sthe technicalterm)andsticksto thecuttingtools,resultingina verypoorsurface nish.This isfarworsethanthenormal halfhardcoppercommercially available(as-castcopper normallycomesoutfully annealed).Theparaf ntrick mentionedatthebeginning ofthearticlecametothe rescueagainandthecopper capswereeasilymachined (photo118)andthenpolished for nal tmenttothechimney.

Machiningthecoppercapseating,withthechimneyfittedtoataperedmandreland aplugpushedintotheotherendtosteadythejobbetweencentres.

Partingoffthechimneycapwithacentrebartopreventthecapfrom clashingwiththetoolpost.Theparaffinmixusedforturningcoppermade machiningmucheasier!

Inletpipingand angemountedwithM2CSKSSscrewsfittedfromtheinside.

Machiningthechimneybore.Withouttheusualchimneycapthecastingiseasierto holdinasmallerchuck.

●Tobecontinued.

IMLEC2023

Wellaheadofthe IMLECcompetition dates,membersof theBristolSocietyofModel Engineersconstructeda trackdegreasingvehiclewith thecuriousnicknameofthe Dribbler,whosesolerolewas tospreaddegreasing uid thinlyontherails,whichwould thenberolledinbyitsownand othertrolleywheels.Thejob seemedtohavebeendonewell and,whenwearrivedtosetup theevent,therailswereclean withrustpatches,showingits effectiveness.Excellent–when it’sdry.

CompetitionDay2–

Saturday

ForSaturday,alldowntothe ‘jetstream’beingsouthofthe UK,TVweatherforecasters weresuggestingtheconditions ofthedaywouldbe‘unsettled’ and,certainly,theearly morningfeelwasalreadyrather differentfromthehotanddry Friday.Ihaveoftennotedthat atAshtonCourttrackyoucan getfourseasonsofweatherin justoneday.

Inanticipationofhostingthe eventforthe rsttimeinmany years,wemadeavideotrailer promotingit(asfarasIknow the rsttimethishasbeen done)andthefeedbackwe receivedwasthatitwaswell liked.Embeddedinitwasthe famousphrase‘anythingcan happeninthenext30minutes’ –thedramahookofoneofthe bestperiodTVshows;sohow wouldwefare?

Saturdaywasanearlier startwiththe rstcontestant duetorunat9amand,while notquitehavingthetenacity ofzealoustouristsplacing reservingtowelsonaTenerife beachfront,ourspectators andcompetitorswerearriving promptlyandpositioning themselvesforaseatedview ofproceedings.

Onthetrack,theruns commence…

Run9(photo9)

FirstoutonSaturdaywasAndy PopefromSouthportMEC,with his3½ inchgaugeSouthern RailwayS15.Thestartofhis runcoincidedwithabriefrain showerand,aftercouplingup tothedynamometercarplus twotrolleys,hislocomotive hadnotractionandwasjust slipping;therainwasacting asalubricant.Afterdropping bothcars,Andymadeittothe startline.Hecommencedhis

runbut,probablyunsettledby theearlierdif culties,losthis pressureonthe rstlapand retired.It’sashamebecause hadAndygotofftoagood startandI’msurehewould havedonemuchbetter.

Run10(photo10)

NextwasDannyHayward,also fromSouthportMEC,witha MaidofKent-alocomotive he rstdroveat10years ofage.Afternotseeingthe locomotiveformanyyears, hemanagedtopurchaseit earlierthisyearthengave

Continuedfromp.311 M.E.4724August25

RobSpeare reportson thisyear’s IMLECheldatBristolon 7th–9thJuly.

PART2

AndyPopeand5inchS154-6-0No.835.

DannyHaywardand5inchLBSC4-4-0MaidofKent.

thebottomhalfafairlyhefty overhaul.Itwasabitdamp asDanny’sruncommenced withthreepassengersbut, withthissensiblylightload, thelocomotivejust ewround, pickingupsomespeeding marksintheprocess.But onlap10thelocomotive slowedandstopped;theaxle boxeswereseizingup,sohe couldnotcompletetherun, exceedingthe35-minutelimit -anotherwiseexcellentrun using2.315lbofcoal.

Run11(photo11)

RogerHollandfromthe Chester eldDMESentered anunusuallocomotivea superbexampleofaUnion Paci cSwitcher,modelled onapreservedexamplein Colorado.Thistall0-6-0with aneightwheeledbogietender wascertainlyaneyecatcher

withthreedomesandaraised bellandapparentlyRogerbuilt itbecausehelikedthetender steps!Withastartingloadof ninepassengersacrossthree carriages,Rogerhadagood rstlapbutonthesecond lapsufferedslippingonthe climbtothestationsoheset backandtriedagain.Roger completedathirdlapbut cametoahaltapproaching thetunnel.Althoughdropping threepassengers,hecouldnot makeitpastthesummitand ranoverthestop-timelimitand retired.Despiteusing3.13lb ofcoal,sadlyRogersaidhe couldn’tgetthelocomotiveto steamproperly.

Run12(photo12)

AndsotoGeorgeWinsall, withamodelofthenarrow gaugeHunslet Russell built byhisgrandfather,thisbeing

George’stenthtimecompeting. Managingtobagadryspell, thiswasastrongrunfromthe outset,goingthedurationof 32:22minuteswithadecent loadoftwelvepassengers maintainedthroughout.George canbecongratulatedonagood performance,withnorecorded stoptimeandcompletingafull elevenlapsusing2.350lbof coal.

Run13(photo13)

AlexLinkinsfromRomney MarshMESwasalsodriving alocomotivebuiltbyhis grandfathertohisown design,intheshapeofa lovelyB.R.liveried5inch BlackFive.Althoughhis rst timeofenteringIMLEC,Alex wasclearlyamasterofthis locomotive.Settingoffwitha loadofninepassengers,the overcastconditionssuited

himashereeledofflapafter lap,althoughitwasnotedhe wastakingonafairamountof water.Hehadafast,consistent run,pickingupaspeedingmark onlaptwelve,althoughhisrun likelywarrantedafewmore. So,using2.275lbofcoal,and nostoptime,Alexcompleteda text-bookrunoffourteenlaps inatimeof30:53.

Run14(photo14)

AnotherSouthEastbased competitor,fromMaidstone MES,TomParhamwasdriving abeautiful5inchgaugemodel ofanLNERA1.Ownedby EdgarPlayfoot,whobuiltitto theMichaelBreezedesign,it wascompletedin2012butin theguiseofthefull-sizenew buildA1 Tornado.Thisgraceful locomotivepurredaround thetrackallowingTomtime toswitchbetweendrinking

RogerHollandand5inchUnionPacificSwitcher0-6-0.

AlexLinkinsand5inchLMSBlack54-6-0.

GeorgeWinsalland3½ inchWelshHighlandRailway2-6-2T Russell

TomParhamand5inchLNERA14-6-2 Tornado.

coffeeandtakingvideos overthecourseofthe32:00 minuterun.Thereisnodoubt thiswasacompetentdrive ofthiswellconstructedthree cylinder4-6-2,withnostop timeencountered.Therewas justmoderateslippingwhile takingthesixteenpassengers onajourneyofthirteenlapsof theAshtontrack,consuming 2.00lbofcoaland nishingin rainyconditions.

Run15(photo15)

Also,fromthe‘locomotive shed’ofMaidstoneMES,Luke Bridgesbroughthis5inch Polly‘Trojan’0-4-0saddle tank,whichhehasmodi ed toimprovetheexhaustand toaiddriving.Dressedinblue ‘PortofLondonAuthority’ colours,Lukealsoentered

thislocomotiveinlastyear’s IMLEC.Withtheweather startingtodeteriorate,Luke’s runstartedinrain,asheset offwithasensiblechoice oftwopassengers.Onthe ascenttothetunnelthough Lukesufferedslippingand hadtosetbackandtakea runatit.Althoughthetrolleys areveryfreerunning,inthese conditionsthisnormallyplucky 0-4-0was ndingithardwork, soLukedecidedtohanguphis shovelaftercompletingtwo laps,thelocomotivehaving consumed1.98lbofcoal.

Run16(photo16)

Anothercompetitorstarting inlightrainwasFareham DSMEmemberChrisDore.He hadenteredhisLNERB1in lastyear’seventbutchoseto

retireaftersufferingslipping problemsindryconditions,so couldhedobetterthisyear? Startingwithaloadofeight passengers,wellinexcessof hislastouting,Chrismanaged asteadyconsistentrunwith thetrackslowlydryingout towardstheend.So,amuch betteryear,successfully completingat31:28minutes, andusing2.170lbofcoal todeliverhisfullloadof passengerstotheirdestination.

Run17(photo17)

LindaGearingfromAndover DMESwasenteringan interestinglocomotive,one thathasevolvedinthe25years sinceastartmadebytwo previousowners.Ithadfurther receivedabespokesaddletank andanewcoatofpaintinthe

shorttimesinceapplyingfor theevent.This0-6-0STalso featuresoutsideStephenson’s valvegear,makingit interestingtowatch.Again, besetbyshoweryconditions, withthreepassengersin tow,Lindasufferedafair degreeofslippingandhad dif cultymaintainingboiler pressure,requiringseveral stopstorestorethe reon thisotherwisespiritedrun. Althoughcompleting velaps, Lindadroppedherpassengers butwasforcedtoretireat 28:00minuteshavingreached themaximumstoptime,witha totalcoalusageof1.125lb.

Run18(photo18)

Ournextentrant,Graham Hickeywasnotonlynewto IMLECbutalsotheonlyentry

LukeBridgesand5inchPollyTrojan0-4-0STNo.53.

LindaGearingand5inchfreelanceMetreMaid0-6-0ST Eric

ChrisDoreand5inchLNERB14-6-0 Nyala

GrahamHickieand5inchSuperSimplex0-6-0T.