Plumier,Bergeron,andmanyotherwriters。
TheworkofPlumierisespeciallyelaborate,enteringintotheconstructionofthelatheinitsvariousparts,themakingofthetoolsandcutters,andthedifferentmotionstobegiventothemachinebymeansofwheels,eccentrics,andotherexpedients,amongstwhichmaybementionedoneverymuchresemblingthesliderestandplaning-machinecombined。*
[footnote……
Itconsistedoftwoparallelbarsofwoodorironconnectedtogetheratbothextremitiesbyboltsorkeysofsufficientwidthtoadmitofthearticlerequiredtobeplaned。Amoveableframewasplacedbetweenthetwobars,motionbeinggiventoitbyalongcylindricalthreadactingonanytoolputintotheslidingframe,and,consequently,causingthescrew,bymeansofahandleateachendofit,topushordrawthepointorcutting-edgeofthetooleitherway——Mr。GeorgeRennie’sPrefacetoBuchanan’sPracticalEssaysonMillWork,3rdEd。xli。
FromthisworkitappearsthatturninghadlongbeenafavouritepursuitinFrancewithamateursofallranks,whosparednoexpenseinthecontrivanceandperfectionofelaboratemachineryfortheproductionofcomplexfigures。*
[footnote……
TurningwasafavouriteamusementamongsttheFrenchnoblesoflastcentury,manyofwhomacquiredgreatdexterityintheart,whichtheyturnedtoaccountwhencompelledtoemigrateattheRevolution。LouisXVI。himselfwasaverygoodlocksmith,andcouldhaveearnedafairlivingatthetrade。OurownGeorgeIII。wasagoodturner,andwaslearnedinwheelsandtreadles,chucksandchisels。HenryMayhewsays,ontheauthorityofanoldworkingturner,that,withaverageindustry,theKingmighthavemadefrom40s。to50s。a-weekasahardwoodandivoryturner。LordJohnHay,thoughone-armed,wasanadeptatthelatter,andLordGraywasanothercapitalturner。IndeedthelateMr。Holtzapffel’selaboratelyillustratedtreatisewaswrittenquiteasmuchforamateursasforworkingmechanics。AmongothernoblehandicraftsmenwemaymentionthelateLordDouglas,whocultivatedbookbinding。LordTraquair’sfancywascutlery,andonecouldnotcometohiminamorewelcomefashionthanwithapairofoldrazorstosetup。
TherewasatthattimeagreatpassionforautomatainFrance,whichgaverisetomanyhighlyingeniousdevices,suchasCamus’sminiaturecarriagemadeforLouisXIV。whenachild,Degennes’mechanicalpeacock,Vancanson’sduck,andMaillardet’sconjuror。Ithadtheeffectofintroducingamongthehigherorderofartistshabitsofniceandaccurateworkmanshipinexecutingdelicatepiecesofmachinery;andthesamecombinationofmechanicalpowerswhichmadethesteelspidercrawl,theduckquack,orwavedthetinyrodofthemagician,contributedinfutureyearstopurposesofhigherimport,——thewheelsandpinions,whichintheseautomataalmosteludedthehumansensesbytheirminuteness,reappearinginmoderntimesinthestupendousmechanismofourself-actinglathes,spinning-mules,andsteam-engines。”Inourowncountry,”saysProfessorWillis,”theliteratureofthissubjectissodefectivethatitisverydifficulttodiscoverwhatprogressweweremakingduringtheseventeenthandeighteenthcenturies。”*
[footnote……
ProfessorWILLIS,LecturesontheResultsoftheGreatExhibitionof1851,lstseries,p。306。
Webelievethefacttobe,thattheprogressmadeinEnglanddowntotheendoflastcenturyhadbeenverysmallindeed,andthatthelathehadexperiencedlittleornoimprovementuntilMaudslaytookitinhand。Nothingseemstohavebeenknownofthesliderestuntilhere-inventeditandappliedittotheproductionofmachineryofafarmoreelaboratecharacterthanhadeverbeforebeencontemplatedaspossible。ProfessorWillissaysthatBramah’s,inotherwordsMaudslay’s,sliderestof1794issodifferentfromthatdescribedintheFrench’Encyclopediein1772,thatthetwocouldnothavehadacommonorigin。WearethereforeledtotheconclusionthatMaudslay’sinventionwasentirelyindependentofallthathadgonebefore,andthathecontriveditforthespecialpurposeofovercomingthedifficultieswhichhehimselfexperiencedinturningoutduplicatepartsinlargenumbers。Atallevents,hewassoearlyandzealousapromoterofitsuse,thatwethinkhemay,intheeyesofallpracticalmechanics,standastheparentofitsintroductiontotheworkshopsofEngland。
ItisunquestionablethatatthetimewhenMaudslaybegantheimprovementofmachine-tools,themethodsofworkinginwoodandmetalswereexceedinglyimperfect。Mr。WilliamFairbairnhasstatedthatwhenhefirstbecameacquaintedwithmechanicalengineering,aboutsixtyyearsago,therewerenoself-actingtools;everythingwasexecutedbyhand。Therewereneitherplaning,slotting,norshapingmachines;andthewholestockofanengineeringormachineestablishmentmightbesummedupinafewill-constructedlathes,andafewdrillsandboringmachinesofrudeconstruction。*
[footnote……
AddressdeliveredbeforetheBritishAssociationatManchesterin1861;andUsefulInformationforEngineers,1stseries,p。22。
Ourmechanicswereequallybackwardincontrivancesforworkinginwood。Thus,whenSirSamuelBenthammadeatourthroughthemanufacturingdistrictsofEnglandin1791,hewassurprisedtofindhowlittlehadbeendonetosubstitutetheinvariableaccuracyofmachineryfortheuncertaindexterityofthehumanhand。Steam-powerwasasyetonlyemployedindrivingspinning-machines,rollingmetals,pumpingwater,andsuchlikepurposes。Intheworkingofwoodnomachineryhadbeenintroducedbeyondthecommonturning-latheandsomesaws,andafewboringtoolsusedinmakingblocksforthenavy。
Evensawsworkedbyinanimateforceforslittingtimber,thoughinextensiveuseinforeigncountries,werenowheretobefoundinGreatBritain。*
[footnote……
LifeofSirSamuelBentham,97-8。
Aseverythingdependedonthedexterityofhandandcorrectnessofeyeoftheworkmen,theworkturnedoutwasofveryunequalmerit,besidesbeingexceedinglycostly。Evenintheconstructionofcomparativelysimplemachines,theexpensewassogreatastopresentaformidableobstacletotheirintroductionandextensiveuse;andbutfortheinventionofmachine-makingtools,theuseofthesteam-engineinthevariousformsinwhichitisnowappliedfortheproductionofpowercouldneverhavebecomegeneral。
Inturningapieceofworkontheold-fashionedlathe,theworkmanappliedandguidedhistoolbymeansofmuscularstrength。Theworkwasmadetorevolve,andtheturner,holdingthecuttingtoolfirmlyuponthelong,straight,guidingedgeoftherest,alongwhichhecarriedit,andpressingitspointfirmlyagainstthearticletobeturned,wasthusenabledtoreduceitssurfacetotherequiredsizeandshape。Somedexterousturnerswereable,withpracticeandcarefulness,toexecuteverycleverpiecesofworkbythissimplemeans。Butwhenthearticletobeturnedwasofconsiderablesize,andespeciallywhenitwasofmetal,theexpenditureofmuscularstrengthwassogreatthattheworkmansoonbecameexhausted。Theslightestvariationinthepressureofthetoolledtoanirregularityofsurface;andwiththeutmostcareontheworkman’spart,hecouldnotavoidoccasionallycuttingalittletoodeep,inconsequenceofwhichhemustnecessarilygooverthesurfaceagain,toreducethewholetothelevelofthataccidentallycuttoodeep;
andthuspossiblythejobwouldbealtogetherspoiledbythediameterofthearticleunderoperationbeingmadetoosmallforitsintendedpurpose。
Theintroductionofthesliderestfurnishedacompleteremedyforthissourceofimperfection。Theprincipleoftheinventionconsistsinconstructingandfittingtherestsothat,insteadofbeingscreweddowntooneplace,andthetoolinthehandsoftheworkmantravellingoverit,therestshallitselfholdthecuttingtoolfirmlyfixedinit,andslidealongthesurfaceofthebenchinadirectionexactlyparallelwiththeaxisofthework。Beforeitsinventionvariousmethodshadbeentriedwiththeobjectofenablingtheworktobeturnedtrueindependentofthedexterityoftheworkman。Thus,asquaresteelcutterusedtobefirmlyfixedinabed,alongwhichitwaswedgedfrompointtopointofthework,andtolerableaccuracywasinthiswaysecured。Butthesliderestwasmuchmoreeasilymanaged,andtheresultwasmuchmoresatisfactory。
Allthattheworkmanhadtodo,afterthetoolwasfirmlyfittedintotherest,wasmerelytoturnascrew-handle,andthusadvancethecutteralongthefaceoftheworkasrequired,withanexpenditureofstrengthsoslightasscarcelytobeappreciable。Andeventhislabourhasnowbeengotridof;for,byanarrangementofthegearing,theslideitselfhasbeenmadeself-acting,andadvanceswiththerevolutionoftheworkinthelathe,whichthussuppliestheplaceoftheworkman’shand。Theaccuracyoftheturningdonebythisbeautifulyetsimplearrangementisasmechanicallyperfectasworkcanbe。Thepairofsteelfingerswhichholdthecuttingtoolfirmlyintheirgraspnevertire,anditmovesalongthemetaltobecutwithanaccuracyandprecisionwhichthehumanhand,howeverskilled,couldneverequal。
Theeffectsoftheintroductionofthesliderestwereveryshortlyfeltinalldepartmentsofmechanism。Thoughithadtoencountersomeoftheridiculewithwhichnewmethodsofworkingareusuallyreceived,andforatimewasspokenofinderisionas”Maudslay’sGo-cart,”——itspracticaladvantagesweresodecidedthatitgraduallymadeitsway,andbecameanestablishedtoolinallthebestmechanicalworkshops。Itwasfoundalikecapableofexecutingthemostdelicateandthemostponderouspiecesofmachinery;andasslide-lathescouldbemanufacturedtoanyextent,machinery,steam-engines,andallkindsofmetalworkcouldnowbeturnedoutinaquantityandatapricethat,butforitsuse,couldneverhavebeenpracticable。Incourseoftimevariousmodificationsofthemachinewereintroduced——suchastheplaningmachine,thewheel-cuttingmachine,andotherbeautifultoolsontheslide-restprinciple,——theresultofwhichhasbeenthatextraordinarydevelopmentofmechanicalproductionandpowerwhichissocharacteristicafeatureoftheagewelivein。”Itisnot,indeed,sayingatalltoomuchtostate,”saysMr。
Nasmyth,*
[footnote……
RemarksontheIntroductionoftheSlidePrincipleinToolsandMachinesemployedintheProductionofMachinery,inBuchanan’sPracticalEssaysonMillWorkandotherMachinery。3rded。p。397。
amostcompetentjudgeinsuchamatter,”thatitsinfluenceinimprovingandextendingtheuseofmachineryhasbeenasgreatasthatproducedbytheimprovementofthesteam-engineinrespecttoperfectingmanufacturesandextendingcommerce,inasmuchaswithouttheaidofthevastaccessiontoourpowerofproducingperfectmechanismwhichitatoncesupplied,wecouldneverhaveworkedoutintopracticalandprofitableformstheconceptionsofthosemastermindswho,duringthelasthalfcentury,havesosuccessfullypioneeredthewayformankind。Thesteam-engineitself,whichsuppliesuswithsuchunboundedpower,owesitspresentperfectiontothismostadmirablemeansofgivingtometallicobjectsthemostpreciseandperfectgeometricalforms。Howcouldwe,forinstance,havegoodsteam-enginesifwehadnotthemeansofboringoutatruecylinder,orturningatruepiston-rod,orplaningavalveface?Itisthisalonewhichhasfurnisheduswiththemeansofcarryingintopracticetheaccumulatedresult’sofscientificinvestigationonmechanicalsubjects。Itwouldbeblamableindeed,”continuesMr。
Nasmyth,”afterhavingendeavouredtosetforththevastadvantageswhichhavebeenconferredonthemechanicalworld,andthereforeonmankindgenerally,bytheinventionandintroductionoftheSlideRest,wereItosuppressthenameofthatadmirableindividualtowhomweareindebtedforthispowerfulagenttowardstheattainmentofmechanicalperfection。IalludetoHenryMaudslay,whoseusefullifewasenthusiasticallydevotedtothegrandobjectofimprovingourmeansofproducingperfectworkmanshipandmachinery:tohimwearecertainlyindebtedforthesliderest,and,consequently,tosaytheleast,weareindirectlysoforthevastbenefitswhichhaveresultedfromtheintroductionofsopowerfulanagentinperfectingourmachineryandmechanismgenerally。Theindefatigablecarewhichhetookininculcatinganddiffusingamonghisworkmen,andmechanicalmengenerally,soundideasofpracticalknowledgeandrefinedviewsofconstruction,haverenderedandeverwillcontinuetorenderhisnameidentifiedwithallthatisnobleintheambitionofaloverofmechanicalperfection。”
OneofthefirstusestowhichMr。Maudslayappliedtheimprovedsliderest,whichheperfectedshortlyafterbeginningbusinessinMargaretStreet,CavendishSquare,wasinexecutingtherequisitetoolsandmachineryrequiredbyMr。afterwardsSirMarcIsambard