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8/3/2019 Carpentry for Boys by James Slough Zerbe
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TheProjectGutenbergEBookofCarpentryforBoys,byJ.S.Zerbe
ThiseBookisfortheuseofanyoneanywhereatnocostandwithalmostnorestrictionswhatsoever.Youmaycopyit,giveitawayorre-useitunderthetermsoftheProjectGutenbergLicenseincludedwiththiseBookoronlineatwww.gutenberg.org
Title:CarpentryforBoysInaSimpleLanguage,IncludingChaptersonDrawing,LayingOutWork,DesigningandArchitectureWith250OriginalIllustrations
Author:J.S.Zerbe
ReleaseDate:March7,2007[EBook#20763]
Language:English
***STARTOFTHISPROJECTGUTENBERGEBOOKCARPENTRYFORBOYS***
ProducedbyRossWilburn,CurtisWeyantandtheOnlineDistributedProofreadingTeamathttp://www.pgdp.net
THE"HOW-TO-DO-IT"BOOKS
CARPENTRYFORBOYS
[Illustration:_Fig.1.ATypicalWorkBench._]
THE"HOW-TO-DO-IT"BOOKS
CARPENTRYFORBOYS
insimplelanguage,includingchaptersondrawing,layingoutwork,designingandarchitecture
WITH250ORIGINALILLUSTRATIONS
BYJ.S.ZERBE,M.E.
AUTHOROF
ELECTRICITYFORBOYSPRACTICALMECHANICSFORBOYS
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THENEWYORKBOOKCOMPANY
NEWYORK
COPYRIGHT,1914,BY
THENEWYORKBOOKCOMPANY
+----------------------------------------------------------------------+|Transcriber'sNotes:Italicsaremarkedbyunderscore(_),Boldtextis||markedby$,Smallcapshavebeenuppercased.|+----------------------------------------------------------------------+
CONTENTS
INTRODUCTORY
I.TOOLSANDTHEIRUSESPage5
KnowledgeofTools.AFullKitofTools.TheHatchet.TheClawHammer.AboutSaws--Cross-cut,RipSaw,BackSaw.Planes--JackPlane,Smoothing
Plane,PorePlane.Gages.Chisels--FirmerChisel.Trusses.SawClamps.TheGrindstone.Oilstone.MiterBox.TheWorkBench.
II.HOWTOGRINDANDSHARPENTOOLSPage16
CareofTools---FirstRequisites.Saws--HowtoSet.Saw-setErrors.SawSettingBlock.Filing.TheAngleofFiling.FilingPitch.SawClamps.FilingSuggestions.TheFile.UsingtheFile.TheGrindstone.IntheUseofGrindstones.CorrectWayofHoldingToolinGrinding.CareofStone.IncorrectWaytoHoldTool.WaytoRevolveorTurnGrindstone.ThePlane.TheGage.Chisels.GeneralObservations.
III.HOWTOHOLDANDHANDLETOOLSPage29
OntheHoldingofTools.TheSaw.HowtoStartaSaw.SawingonaLine.TheFirstStroke.TheStartingCutforCross-cutting.ForcingaSaw.TheStroke.TheChineseSaw.ThingstoAvoid.ThePlane.AngleforHoldingPlanes.ErrorstobeAvoided.TheGage.HoldingtheGage.TheDraw-knife.
IV.HOWTODESIGNARTICLESPage39
FundamentalsofDesigning.TheCommercialInstinct.FirstRequirementsofDesigning.ConventionalStyles.TheMissionStyle.Cabinets.HarmonyofParts.HarmonyofWood.
V.HOWWORKISLAIDOUTPage43
ConcreteExamplesofWork.Dimensions.LayingOutaTable.TheTop.TheMortises.TheFacingBoards.TheTenons.ToolsUsed.ChamferedTenons.TheFrame.TheDrawerSupport.TheTableFrame.TheTop.TheDrawer.HowAnyStructureisBuiltUp.ObservationsAboutMakingaBox.Points.BevelingandMitering.ProperTerms.PictureFrames.DovetailPoints.BoxPoints.FirstStepsinDovetailing.CuttingOuttheSpaces.ToolsUsedinLayingOutMortisesandTenons.
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VI.THEUSESOFTHECOMPASSANDTHESQUAREPage59
TheCompass.DeterminingAngles.DefinitionofDegrees.DegreesWithoutaCompass.HowDegreesareCalculatedbytheDividers.
VII.HOWTHEDIFFERENTSTRUCTURALPARTSAREDESIGNATEDPage65
ImportanceofProperDesignation.HowtoExplainMechanicalForms.DefiningSegmentandSector.Arcade,Arch,Buttress,FlyingButtress,Chamfer,Cotter,Crenelated,Crosses,CurbRoof,Cupola,CrownPost,Corbels,Dormer,Dowel,Drip,Detent,Extrados,Engrailed,Facet,Fret,Fretwork,Frontal,Frustrums,Fylfot,GambrelRoof,Gargoyle,Gudgeon,Guilloche.HalfTimbered,HammerBeam,Header,HipRoof,HoodMolding,Inclave,InterlacingArch,Inverted,InvertedArch,KeyStone,KingPost,Label,Louver,Lintel,Lug,M-Roof,MansardRoof,Newel,Parquetry,Peen,Pendant,Pendastyle,Pedestal,Plinth,Portico,Plate,QueenPost,QuirkMolding,Re-enteringAngle,Rafter,Scarfing,ScotiaMolding,Sill,Skewback,Spandrel,Strut,Stud,Stile,TieBeam,Timber,Trammel,Turret,Transom,ValleyRoof.
VIII.DRAWINGANDITSUTILITYPage73
FundamentalsinDrawing.RepresentingObjects.FormingLinesandShadows.AnalysisofLinesandShadings.HowtoShowPlainSurfaces.
ConcaveSurfaces.ConvexSurfaces.ShadowsfromaBeam.FlatEffects.TheDirectionofLight.RaisedSurfaces.DepressedSurfaces.FullShading.IllustratingCubeShading.ShadingEffect.HeavyLines.Perspectives.TruePerspectiveofaCube.IsometricCube.FlattenedPerspective.TechnicalDesignations.SectorandSegment.TermsofAngles.CirclesandCurves.IrregularCurves.EllipsesandOvals.FocalPoints.ProducedLine.Spirals,PerpendicularandVertical.SignstoIndicateMeasurement.Definitions.Abscissa.Angle.Apothegm.ApsidesorApsis.Chord.Cycloid.Conoid.ConicSection.Ellipsoid.Epicycloid.Evolute.FlyingButtress.Focus.Gnomes.Hexagon.Hyperbola.Hypothenuse.Incidental.Isosceles.Triangle.Parabola.Parallelogram.Pelecoid.Polygons.Pyramid.Rhomb.Sector.Segment.Sinusoid.Tangent.Tetrahedron.Vertex.
IX.MOLDINGS,WITHPRACTICALILLUSTRATIONSINEMBELLISHINGWORKPage93
Moldings.TheBasisofMoldings.TheSimplestMoldings.TheAstragal.TheCavetto.TheOvolo.TheTorus.TheApothegm.TheCymatium.TheOgee.OgeeRecta.OgeeReversa.TheReedy.TheCasement.TheRoman-DoricColumn.LessonfromtheDoricColumn.ApplyingMolding.Base.Embellishments.Straight-facedMolding.PlainMolding.Base.DiversifiedUses.ShadowsCastbyMoldings.
X.ANANALYSISOFTENONING,MORTISING,RABBETINGANDBEADINGPage104
WhereMortisesShouldbeUsed.DepthofMortises.RuleforMortises.
TrueMortiseWork.StepsinCuttingMortises.ThingstoAvoidinMortising.Lap-and-ButtJoints.Scarfing.TheTongueandGroove.Beading.OrnamentalBeadFinish.TheBeadandRabbet.ShadingwithBeadsandRabbets.
XI.HOUSEBUILDINGPage113
HouseBuilding.TheHomeandEmbellishments.BeautyNotOrnamentation.PlainStructures.ColonialType.TheRooftheKeynote.BungalowTypes.GeneralHouseBuilding.BuildingPlans.ThePlainSquare-FloorPlan.The
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RectangularPlan.RoomMeasurements.FrontandSideLines.TheRoof.RoofPitch.TheFoundation.TheSills.TheFlooringJoist.TheStudding.SettingUp.ThePlate.IntermediateStudding.WallHeaders.CeilingJoist.Braces.TheRafters.TheGutter.SettingDoorandWindowFrames.PlasteringandFinishWork.
XII.BRIDGES,TRUSSEDWORKANDLIKESTRUCTURESPage130
Bridges.Self-supportingRoofs.CommonTrusses.TheVerticalUprightTruss.TheWarrenGirder.TheBowstringGirder.FundamentalTrussForms.
XIII.THEBESTWOODSFORTHEBEGINNERPage134
TheBestWoods.SoftWoods.HardWoods.TheMostDifficultWoods.TheHard-ribbedGraininWood.TheEasiestWorkingWoods.DifferencesintheWorkingofWoods.ForcingSawsinWood.
XIV.WOODTURNINGPage138
AdvantagesofWoodTurning.SimpleTurningLathe.TheRails.TheLegs.CenteringBlocks.TheTail-stock.TheToolRest.Materials.TheMandrel.Fly-wheel.TheToolsRequired.
XV.ONTHEUSEOFSTAINSPage147SoftWood.UseofStains.StainsasImitations.GoodTasteinStaining.GreatContrastsBad.StainingContrastingWoods.HardWoodImitations.NaturalEffects.NaturalWoodStains.PolishingStainedSurfaces.
XVI.THECARPENTERANDTHEARCHITECTPage152
XVII.USEFULARTICLESTOMAKEPage155
CommonBench.ItsProportions.SquareTopStool.FoldingBlackingBox.ConvenientEasel.HangingBook-rack.SadIronHolder.Bookcase.Wood-box.ParallelBarsforBoys'Use.MissionWritingDesk.Screen
Frame.MissionChair.Grandfather'sClock.KnockdownandAdjustableBookcase.CoalScuttleFrameorCase.MissionArmChair.Dog-house.Settle,WithConvenientShelves.TowelRack.SofaFramework.
XVIII.SPECIALTOOLSANDTHEIRUSESPage170
BitandLevelAdjuster.MiterBoxes.SwivelArmUprights.MovableStops.AngleDividers."OddJob"Tool.BitBraces.RatchetMechanism.InterlockingJaws.SteelFrameBreastDrills.HorizontalBoring.3-JawChuck.Planes.Rabbeting,BeadingandMatching.CutterAdjustment.DepthGage.SlittingGage.DovetailTongueandGroovePlane.RouterPlanes.BottomSurfacing.DoorTrimPlane.
XIX.ROOFINGTRUSSESPage185
CharacteristicsofTrusses.TieBeams.Ornamentation.ObjectsofBeams,StrutsandBraces.UtilizingSpace.TypesofStructures.GambrelRoof.PurlinRoof.ThePrincessTruss.Arched,orCambered,TieBeamTruss.TheMansard.ScissorsBeam.BracedCollarBeam.RibandCollarTruss.Hammer-beamTruss.FlyingButtress.
XX.ONTHECONSTRUCTIONOFJOINTSPage197
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DefinitionandUses.DifferentTypes.BridleJoint.SpurTenon.SaddleJoints.JoggleJoint.HeelJoints.StubTenon.TuskTenon.DoubleTuskTenon.CoggedJoints.AnchorJoints.DeepAnchorJoints.
XXI.SOMEMISTAKESANDALITTLEADVICEINCARPENTRYPage205
LessonsFromMistakes.PlaningtheEdgeofaBoardStraight.PlaningitSquare.PlaningtoDimensions.HoldingthePlane.HowitShouldbeRunontheEdgeoftheBoard.TruingWiththeWeightofthePlane.ASteadyGrasp.InSmoothingBoards.CorrectSand-papering.Gluing.RemovingSurplusGlue.WorkEdgeandWorkSide.TheScribingandMarkingLine.FinishingSurfaces.SawingaBoardSquare.TheStrokeoftheSaw.SawingOutofTrue.
LISTOFILLUSTRATIONS
FIG.
1.AtypicalworkbenchFrontispiecePAGE
2.Hatchet63.Hammer74.Commonsaw75.Plane86.Jackplanebit96a.Foreplanebit107.Firmerchisel117a.Mortisingchisel128.Trestle129.Miterbox1310.Incorrectsawsetting1710a.Correctsawsetting1711.Sawsettingdevice17
12.Filingangle1813.Ripsaw1914.Crosscut2015.Filingclamp2116.Grindstone2317.Correctmannerofholdingtool2418.Incorrectwayofholdingtool2419.Gage2620.Startingasaw3121.Wrongsawingangle3222.Correctsawingangle3323.Thrustcut3424.Chinesesaw34
25.Movingangleforplane3526.Holdinggage3627.Layingouttableleg4328.Thefirstmarkingline4429.Scribingmortiseline4430.Thecornermortises4431.Thesiderail4632.Scribingthetenons4633.Crossscoring4734.Thetenon47
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35.Finishingthetenon4736.Thetenonandmortise4837.Thedrawersupport4838.Drawercleats4939.Assembledtableframe5040.Thetop5141.Thedrawer5242.Beveljoint5343.Miterjoint5344.Pictureframejoint5445.Initialmarksfordovetails5546.Endmarksfordovetails5547.Anglesfordovetails5548.Cuttingoutrecessesfordovetails5649.Tonguesfordovetails5650.Recessfordovetails5651.Determiningangles6152.Markingdegrees6353.Anglesfrombaselines6354.Steppingoffspaces6355.Arcade6756.Arch6757.Buttress6758.Chamfer67
59.Cooter6760.Crenelated6761.Crosses6762.Curbroof6763.Cupola6764.Console6765.Corbels6766.Dormer6767.Dowel6768.Drips6769.Detail6870.Extrados6871.Engrailed68
72.Facet6873.Fret6874.Frontal6875.Frustrums6876.Fylfat6877.Gambrel6878.Gargoyle6879.Gudgeon6880.Guilloche6881.Halftimbered6882.Hammerbeam6883.Haunches6984.Header69
85.Hiproof6986.Hoodmolding6987.Inclave6988.Interlacingarch6989.Invected6990.Invertedarch6991.Keystone6992.Kingpost6993.Label6994.Louver69
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95.Lintel7096.Lug7097.M-roof7098.Mansardroof7099.Newelpost70100.Parquetry70101.Peen,orpein70102.Pendant70103.Pentastyle70104.Pedestal70105.Pintle70106.Portico70107.Plate70108.Queenpost71109.Quirkmolding71110.Re-entering71111.Rafter71112.Scarfing71113.Scotiamolding71114.Sill71115.Skewback71116.Spandrel71117.Strut71118.Stud,studding71
119.Stile72120.Trammel72121.Turret72122.Transom72123.Valleyroof72125.Plainline74126.Concaveshading74127.Convexshading74128.Waveshading75129.Lightpastconcavesurface75130.Lightpastconvexsurface75131.Plainsurface75132.Outlines76
133.Raisedsurface77134.Depressedsurface77135.Shadingraisedsurfaces78136.Shadingdepressedsurfaces78137.Plaincubicaloutline79138.Indicatingcube79139.Confusedlines79140.Heavyhorizontallines80141.Heavyverticallines80142.Isometriccube81143.Cubeandcircle81144.Flattenedperspective82145.Anglesinisometriccube83
146.Plaincircle84147.Sphereshading84148.Drawingregularellipse86149.Drawingirregularellipse88150.Drawingspiral89151.Abscissa90152.Angle91153.Apothegm91154.Apsides,orapsis91155.Chord91
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156.Convolute91157.Conicsections91158.Conoid91159.Cycloid91160.Ellipsoid91161.Epicycloid91162.Evolute91163.Focus91164.Gnome91165.Hyperbola91167.Hypothenuse91168.Incidence92169.Isoscelestriangle92170.Parabola92171.Parallelogram92172.Pelecoid92173.Polygons92174.Pyramid92175.Quadrant92176.Quadrilateral92177.Rhomb92178.Sector92179.Segment92180.Sinusoid92
181.Tangent92182.Tetrahedron92183.Vertex92184.Volute92185.Band(molding)94186.Astragal(molding)94187.Cavetto(molding)94188.Ovolo(molding)94189.Torus(molding)95190.Apophyges(molding)95191.Cymatium(molding)95192.Ogee-recta(molding)95193.Ogee-reversa(molding)96
194.Bead(molding)96195.Casement(molding)97196.TheDoriccolumn98197.Frontofcabinet100198.Faciaboard100199.Moldingonfaciaboard100200.Ogee-rectaonfacia101201.Trimbelowfacia101202.Trimbelowogee101203.Trimabovebase102204.Trimabovebasemolding102205.Shadowscastbyplainmoldings103206.Mortiseandtenonjoint105
207.Incorrectmortising105208.Stepsinmortising106209.Theshouldersoftenons108210.Lap-and-buttjoint108211.Paneljoint109212.Scarfing109213.Tongueandgroove110214.Beading110215.Outsidebeadingfinish110216.Edgebeading111
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217.Cornerbeading111218.Pointbeading111219.Roundedgebeading111220.Beadingandmolding111221.Firstsquarehouseplan117222.Firstrectangularhouseplan118223.Squarehousetoscale119224.Rectangularhousetoscale120225.Frontelevationofsquarehouse121226.Elevationofrectangularhouse121227.Illustratingone-thirdpitch122228.Illustratinghalfpitch122229.Thesillsatthecorner123230.Thejoistandsills123231.Theplatesplice124232.Therafters125233.Thegutter126234.Thecornice127234a.Thefinishwithoutgutter128235.Commontruss130236.Uprighttruss131237.Verticaluprighttruss131238.Warrengirder132239.ExtendedWarrengirder132
240.Bowstringgirder132241.Framedetailsofwoodturninglathe139242.Tailstockdetails140243.Toolrestdetails142244.Sectionofmandrel143245.Viewofturninglathe145246.Turningtools146247.Bench155248.Stool156249.Blackingbox156250.Easel157251.Hangingbookrack158252.Bookshelf159
253.Woodbox160254.Horizontalbars161255.Missiondesk161256.Screenframe162257.Missionchair162258.Grandfather'sclock163259.Frameforbookcase164260.Coalscuttlecase165261.Missionarmchair165262.Doghouse168263.Settle167264.Towelrack168265.Missionsofaframe168
266.Bitandsquarelevel170267.Metalmiterbox171268.Partsofmetalmiterbox172269.Angledividers173270.An"oddjob"tool174271.Universal-jawbrace176272.Taper-shankbitbrace176273.Alligator-jawbrace176274.Steelframebreastdrill177275.Steelframebreastdrill177
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276.Steelframebreastdrill177277.Detailsofmetalplane179278.Rabbet,matchinganddadoplane180279.Moldingandbeadingplane181280.Dovetailtongueandgrooveplane182281.Routerplanes183282.Routerplanes183283.Doortrimplane184284.Gambrelroof187285.Purlinroof188286.Princesstruss189287.Arched,orcambered,tiebeam190288.Themansard191289.Scissorsbeam192290.Bracedcollarbeam193291.Ribandcollartruss194291-1/2.Hammer-beamtruss195292.Bridlejoints197293.Spurtenons198294.Saddlejoints198295.Jogglejoints199296.Framingjoints199297.Heeljoints200298.Stubtenon200
299.Tusktenon201300.Doubletusktenon202301.Coggedjoints203302.Anchorjoint203303.Deepanchorjoint204
CARPENTRY
APRACTICALCOURSE,WHICHTELLSINCONCISEANDSIMPLEFORM"HOWTODOIT"
INTRODUCTORY
Carpentryistheoldestofthearts,andithasbeensaidthattheknowledgenecessarytomakeagoodcarpenterfitsoneforalmostanytradeoroccupationrequiringtheuseoftools.Thehatchet,thesaw,andtheplanearethethreeprimalimplementsofthecarpenter.Thevalueisinknowinghowtousethem.
TheinstitutionofManualTrainingSchoolseverywhereisbutatardyrecognitionofthevalueofsystematictrainingintheuseoftools.Thereisnobranchofindustrywhichneedssuchdiversification,inordertobecomeefficient.
Theskilloftheblacksmithiscenteredinhisabilitytoforge,toweld,andtotemper;thatofthemachinistdependsuponthecallipereddimensionsofhisproduct;thepainterinhistasteforharmony;themasononhisabilitytocutthestoneaccurately;andtheplastererto
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produceauniformsurface.Butthecarpentermust,inordertobeanexpert,combineallthesequalifications,inagreaterorlessdegree,andhisvocationmayjustlybecalledtheKingofTrades.Rightly,therefore,itshouldbecultivatedinordertolearntheessentialsofmanualtrainingwork.
Butthereisanotherfeatureoftheutmostimportanceandvalue,whichisgenerallyoverlooked,andonwhichthereisplacedtoolittlestress,eveninmanyofthemanualtrainingschools.Thetrainingofthemindhasbeensystematizedsoastobringintooperationtheenergiesofallthebraincells.Manualtrainingtobeefficientshould,atthesametime,bedirectedintosuchchannelsaswillmostwidelystimulatethemusculardevelopmentofthechild,whileatthesametimecultivatinghismind.
Thereisnotradewhichofferssuchausefulfieldascarpentry.Itmaybesaidthatthevariousmanualoperationsbringintoplayeverymuscleofthebody.
Thesaw,theplane,thehammer,thechisel,eachrequiresitsspecialmuscularenergy.Thecarpenter,unliketheblacksmith,doesnotputallhisbrawnintohisshoulders,nordevelophistorsoattheexpenseofhisothermuscles,likethemason.Itmayalsobesaidthat,unlikemostotheroccupations,thecarpenterhasbothout-of-doorandindoor
exercise,sothatheisatalltimesabletofollowhisoccupation,summerorwinter,rainorshine;andthisalsofurtherillustratesthevalueofthisbranchofendeavorasahealthfulrecreation.
Itistheaimofthisbooktoteachboystheprimaryrequirements--nottogeneralize--buttoshowhowtoprepareandhowtodothework;whattoolsandmaterialstouse;andinwhatmannerthetoolsusedmaybemademostserviceable,andusedmostadvantageously.
Itwouldbeofnovaluetodescribeandillustratehowabracketismade;orhowtheframeworkofastructureisprovidedwithmortisesandtenonsinordertoholdittogether.Theboymusthavesomethingasabasewhichwillenablehimtodesignhisowncreations,andnotbean
imitator;hismindmustdevelopwithhisbody.Itistheprincipalaimofthisbooktogivetheboysomethingtothinkaboutwhileheislearninghowtobringeachindividualparttoperfection.
Iftheboyunderstandsthatthereisaprincipleunderlyingeachstructuraldevice;thatthereisareasonformakingcertainthingsadefiniteway,heisimbuedwithanincentivewhichwillsoonerorlaterdevelopintoaninitiativeofhisown.
Itisthisphaseintheartisan'slifewhichdetermineswhetherhewillbemerelyamachineoranintelligentorganism.
Thisworkputstogetherinasimple,conciseform,notonlythe
fundamentalswhicheverymechanicshouldlearntoknow,butitdefineseverystructuralformusedinthisart,andillustratesalltermsitisnecessarytouseintheemploymentofcarpentry.Afullchapterisdevotedtodrawingspracticallyapplied.Alltermsarediagrammedanddefined,sothatthemindmayreadilygrasptheideasinvolved.
Finally,itwillbeobservedthateveryillustrationhasbeenspeciallydrawnforthisbook.Wehavenotadoptedtheplanusuallyfollowedinbooksofthisclass,oftakingstockillustrationsofmanufacturers'toolsanddevices,norhavewethoughtitadvisabletotakeapictureof
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atooloramachineandthenwriteadescriptionaroundit.Wehaveillustratedthebooktoexplain"_howtodothework_";also,toteachtheboywhatthetraderequires,andtogivehimthemeanswherebyhemayreadilyfindtheformofeverydevice,tool,andstructureusedintheart.
CHAPTERI
TOOLSANDTHEIRUSES
KNOWLEDGEOFTOOLS.--Aknowledgeoftoolsandtheirusesisthefirstandmostimportantrequirement.Thesaw,theplane,thehatchetandthehammerarewellknowntoallboys;buthowtousethem,andwheretousethedifferentvarietiesofeachkindoftool,mustbelearned,becauseeachtoolgrewoutofsomeparticularrequirementintheart.Theseuseswillnowbeexplained.
AFULLKITOFTOOLS.--Akitoftoolsnecessaryfordoinganyplainworkshouldembracethefollowing:
1.AHatchet.2.AClawHammer--twosizespreferred.3.Cross-cutSaw,20incheslong.4.RipSaw,24incheslong.5.WoodenMallet.6.JackPlane.7.SmoothingPlane.8.CompassSaw.9.Brace.10.BitsforBrace,rangingfrom1/4inchto1inchdiameter.11.SeveralsmallGimlets.12.Square.
13.Compass.14.Draw-knife.15.Rule.16.TwoGages.17.SetofFirmerChisels.18.TwoMortisingChisels.19.SmallBackSaw.20.SawClamps.21.MiterBox.22.BevelSquare.23.SmallHandSquare.24.Pliers.25.PairofAwls.
26.HandClamps.27.SetFiles.28.GluePot.29.OilStone.30.Grindstone.31.Trusses.32.WorkBench.33.PlumbBob.34.SpiritLevel.
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THEHATCHET.--Thehatchetshouldbegroundwithabeveloneachside,andnotononesideonly,asiscustomarywithaplasterer'slathinghatchet,becausethebladeofthehatchetisusedfortrimmingofftheedgesofboards.Unlessgroundoffwithabevelonbothsidesitcannotbecontrolledtocutaccurately.Alighthatchetispreferabletoaheavyone.Itshouldneverbeusedfornailingpurposes,exceptinemergencies.Thepoleofthehammer--thatpartwhichisgenerallyusedtostrikethenailwith--isrequiredinordertoproperlybalancethehatchetwhenusedfortrimmingmaterial.
[Illustration:_Fig.2._]
THECLAWHAMMER.--Thisisthepropertoolfordrivingnailsandfordrawingthemout.Habitsshouldbeformedwiththebeginner,whichwillbeofgreatserviceastheeducationproceeds.
Oneofthesehabitsistopersistinusingthetoolforthepurposeforwhichitwasmade.Theexpertworkman(andhebecomesexpertbecauseofit)makesthehammerdoitsproperwork;andsowitheveryothertool.
[Illustration:_Fig.3._]
[Illustration:_Fig.4._]
ABOUTSAWS.--Therearefourwell-definedkinds.First,along,flatsaw,forcross-cutting.Second,aslightlylargersawforrippingpurposes.Third,abacksaw,witharibontherearedgetoholdthebladerigid,usedformakingtenons;and,fourth,acompassorkeyholesaw.
CROSS-CUTS.--Thedifferencebetweenacross-cutandaripsawis,thatinthelattertheteethhavelesspitchandareusuallylargerthaninthecross-cutsaw.Theillustrations(Figs.13and14)willdistinctlyshowthedifferenceintheteeth.Whenacross-cutsawisusedforrippingalongthegrainofthewood,theteeth,ifdisposedatanangle,willrideoverthegrainorfiberofthewood,andrefusetotakeholdorbiteintothewood.Ontheotherhand,iftheripsawisusedfor
cross-cuttingpurposes,thesawkerfwillberoughandjagged.
[Illustration:_Fig.5._]
Thebacksawisusedalmostexclusivelyformakingtenons,andhasuniformlyfineteethsoastogiveasmoothfinishtothewood.
PLANES.--Theplanemaybecalledthesthetictoolinthecarpenter'skit.Itisthemostdifficulttooltohandleandthemostsatisfactorywhenthoroughlymastered.Howtocareforandhandleitwillbereferredtoinasubsequentchapter.Wearenowconcernedwithitsusesonly.Eachcompletekitmusthavethreedistinctplanes,namely,thejackplane,whichisfortakingofftheroughsawprintsurfaceofthe
board.Theshortsmoothingplane,whichisdesignedtoevenuptheinequalitiesmadebythejackplane;andthelongfinishingplane,orforeplane,whichisintendedtostraightentheedgesofboardsoroffinishedsurfaces.
[Illustration:_Fig.6.Jackplanebit._]
THEJACKPLANE.--Thisplanehasthecuttingedgeofitsbladegroundsoitisslightlycurved(Fig.6),because,asthebitmustbedrivenoutsoitwilltakeadeepbiteintotheroughsurfaceofthewood,the
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curvedcuttingedgepreventsthecorneredgesofthebitfromdiggingintotheplanedsurface.
Ontheotherhand,thebitsofthesmoothingandfinishingplanesaregroundstraightacrosstheircuttingedges.Intheforegoingwehavenotenumeratedthedifferentspecialplanes,designedtomakebeads,rabbets,tonguesandgrooves,buteachtypeisfullyillustrated,sothatanideamaybeobtainedoftheircharacteristics.(Fig.6_a_).
GAGES.--Oneofthemostvaluabletoolsinthewholesetisthegage,butitis,infact,theleastknown.Thisissimplyastraightbar,withasharpenedpointprojectingoutononesidenearitsend,andhavinganadjustableslidingheadorcheekpiece.Thistoolisindispensableinmakingmortisesortenons,becausethesharpenedsteelpointwhichprojectsfromthesideofthebar,servestooutlineanddefinetheedgesofthemortisesortenons,sothatthecuttinglinemayreadilybefollowed.
[Illustration:_Fig.6a.Fore-planebit._]
Thisisthemostdifficulttooltoholdwheninuse,butthatwillbefullyexplainedunderitsproperhead.Eachkitshouldhavetwo,asinmakingmortisesandtenonsonegageisrequiredforeachsideofthemortiseortenon.
CHISELS.--Twokindsarefoundineverykit--onecalledthefirmer(Fig.7)andthemortisingchisel.Thefirmerhasaflatbodyorblade,andafullsetrangesinwidthfromthree-eighthsofaninchtotwoinches.Thesizesmostdesirableandusefularetheone-halfinch,theinchandtheinch-and-a-halfwidths.Theseareusedfortrimmingoutcrossgrainsorrebatesforsettingdoorlocksandhingesandfornumerousotheruseswheresharp-endtoolsarerequired.
[Illustration:_Fig.7._]
THEMORTISINGCHISEL.--Themortisingchisel(Fig.7_a_),ontheotherhand,isverynarrowandthick,withalongtaperdowntothecutting
edge.Theyareusuallyinsuchwidthsastomakethemstocksizesformortises.Never,underanycircumstances,useahammerorhatchetfordrivingchisels.Themalletshouldbeusedinvariably.
[Illustration:_Fig.7a._]
TRUSSES.--Thereshouldbeatleasttwo,eachthreefeetinlengthandtwentyinchesinheight.
SAWCLAMPS.--Thesearenecessaryadjuncts,andshouldbemadeofhardwood,perfectlystraightandjustwideenoughtotakeinthenarrowbacksaw.Theillustrationshowstheirshapeandform.
THEGRINDSTONES.--Itisbettertogetafirst-classstone,whichmaybesmallandriggedupwithafoottreadle.Asoft,fine-grainedstoneismostserviceable,anditshouldhaveawatertray,andneverbeusedexceptingwithplentyofwater.
[Illustration:_Fig.8._]
ANOILSTONEisasessentialasagrindstone.Forgivingagoodedgetotoolsitissuperiortoawaterstone.Itshouldbeprovidedwithatop,andcoveredwhennotinuse,tokeepoutdustandgrit.Thesearethe
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littlethingsthatcontributetosuccessandshouldbecarefullyobserved.
THEMITERBOX.--Thisshouldbe14incheslongand3"by3"inside,madeofhardwood3/4"thick.Thesidesshouldbenailedtothebottom,asshown.
[Illustration:_Fig.9._]
THEWORKBENCH.--Initsproperplaceweshowindetailthemostapprovedformofworkbench,fittedwithatoolracktoholdallthetools,convenientlyarranged.Inthischapterwearemoreparticularlyconcernedwiththeusesoftoolsthantheirconstruction;andweimpressonboysthenecessityofhavingaplaceforeverything,andthateverytoolshouldbekeptinitsproperplace.Acarpenter'sshopfilledwithchips,shavingsandotherrefuseisnotadesirableplacefortheindiscriminateplacingoftools.Ifcorrecthabitsareformedattheoutset,bycarefullyputtingeachtoolinitsplaceafterusing,itwillsavemanyanhourofuselesshuntingandannoyance.
Oneofthemostimportantthingsinlayingoffwork,forinstance,ontrusses,isthedispositionofthesawandsquare.Ourillustrationshowseachtrusswithsidecleats,whichwillpermittheusertemporarilytodepositthesaworthesquaresothatitwillbehandy,
andatthesametimebeoutofthewayoftheworkandpreventeitherofthetoolsfrombeingthrowntothefloor.
Inthesameway,andforthesamepurpose,theworkbenchhastemporaryholdingcleatsattheendandashelfinfront,whichareparticularlydesirable,becauseeitherasaworasquareisanencumbranceonaworkbenchwhiletheworkisbeingassembled,andtoolsofthiskindshouldnotbelaidflatonaworkingsurface,norshouldtheybestoodinaleaningpositionagainstatrussorworkbench.
_Strictlyobservethesefundamentals_--Neverplaceatoolwiththecuttingedgetowardyou.Alwayshavetheracksorreceptaclessomadethatthehandlemaybeseized.Don'tputatoolwithanexposedcutting
edgeaboveorbelowanothertoolinsuchamannerthatthehandorthetoolyouarehandlingcancomeintocontactwiththeedge.Neverkeepthenailorscrewboxesabovetheworkbench.Theyshouldalwaysbekepttooneside,toprevent,asmuchaspossible,thebenchfrombecomingadepositoryfornails.Keepthetopofthebenchfreefromtools.Alwayskeeptheplanesonanarrowsub-shelfattherearofthebench.
IforderwasHeaven'sfirstlaw,itisagoodprincipletoapplyitinaworkman'sshop,anditsobservancewillformahabitthatwillsoonbecomeapleasuretofollow.
CHAPTERII
HOWTOGRINDANDSHARPENTOOLS
CAREOFTOOLS.--Dulltoolsindicatethecharacteroftheworkman.Inanexperienceofoverfortyyears,Ihaveneverknownagoodworkmantokeeppoorlysharpenedtools.Whileitistruethatthecapacitytosharpentoolscanbeacquiredonlybypractice,correcthabitsatthe
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startwillmateriallyassist.Indoingthispartoftheartisan'swork,itshouldbeunderstoodthatthereisarightaswellasawrongway.
Thereisaprincipleinvolvedinthesharpeningofeverytool,whichshouldbeobserved.Askilledartisanknowsthatthereisaparticularwaytogrindthebitsofeachplane;thatthemannerofsettingasawnotonlycontributestoitsusefulness,butwillmateriallyaddtothelifeofthesaw;thatachiselcannotbemadetodogoodworkunlessitscuttingedgeissquareandattherightworkingangle.
FIRSTREQUISITE.--Abeginnershouldneverattemptapieceofworkuntilhelearnshowthedifferenttoolsshouldbesharpened,oratleastlearntheprincipleinvolved.Practicewillmakeperfect.
SAWS.--Asthesawissuchanimportantpartofthekit,Ishalldevotesomespacetothesubject._First_,astosettingthesaw.Theobjectofthisistomaketheteethcutawiderkerfthanthethicknessoftheblade,andtherebycausethesawtotravelfreely.Agreatmanyso-called"sawsets"arefoundinthemarket,manyofthembuiltonwrongprinciples,aswillbeshown,andtheseareincapableofsettingaccurately.
[Illustration:_Fig.10._]
[Illustration:_Fig.10a._][Illustration:_Fig.11._]
HOWTOSET.--Tosetasawaccurately,thatis,todriveouteachtooththesamedistance,isthefirstrequirement,andthesecondistobendoutthewholetooth,andnotthepointonly.
Intheillustration(Fig.10),thepointismerelybentout.Thisiswrong.TherightwayisshowninFig.10_a_.Thewholetoothisbent,showingthecorrectwayofsetting.Thereasonsforavoidingonewayandfollowingtheotherare:First,thatifthepointprojectstooneside,eachpointortoothwilldigintothewood,andproducetoothprintsin
thewood,whichmakearoughenedsurface.Second,thatifthereareinequalitiesinsettingtheteeth(asissuretobethecasewhenonlythepointsarebentout),themostexposedpointswillfirstwearout,andtherebycausesawdeterioration.Third,asawwiththepointsstickingoutcausesaheavy,draggingcut,andmeansadditionallabor.Wherethewholebodyofthetoothisbent,thesawwillrunsmoothlyandeasilythroughthekerfandproduceasmooth-cutsurface.
[Illustration:_Fig.12._]
Ourillustration(Fig.11)showsaverysimplesettingblock,theprincipalmeritofwhichisthatanyboycanmakeit,andintheuseofwhichhecannotgowronginsettingatooth.
SIMPLESAWSETTER.--Takeablockofwood,a4by4inchstudding,fourincheslong.Getapieceofmetalone-halfinchthickandtwoinchessquare.Haveablacksmithormachinistboreaquarter-inchholethroughitinthecenterandcountersinktheuppersidesoitmaybesecurelyfastenedinamortiseintheblock,withitsuppersideflushwiththeuppersurfaceoftheblock.Now,withafile,finishoffoneedge,goingbackforaquarterofaninch,theangleatAtobeabout12degrees.
[Illustration:_Fig.13.Rip-Saw._]
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FILINGANGLES.--Initsproperplacewillbeshownhowyoumayeasilycalculateandmeasuredegreesinworkofthiskind.Fig.12showsanapproximationtotherightangle.B,B(Fig.11)shouldbeapairofwoodenpegs,drivenintothewoodenblockoneachsideofthemetalpiece.Theteethofthesawrestagainstthepegssothattheyserveasaguideoragage,andtheteethofthesaw,therefore,projectovertheinclinedpart(B)ofthemetalblock.Now,withanordinarypunchandahammer,eachalternatetoothmaybedrivendownuntilitrestsflatontheinclinedface(A),sothatitisimpossibletosettheteethwrongly.Whenyouglancedowntheendofaproperlysetsaw,youwillseeaV-shapedchannel,andifyouwillplaceaneedleinthegrooveandholdthesawatanangle,theneedlewilltraveldownwithoutfallingout.
[Illustration:_Fig.14.cross-cut._]
FILING.--Thenextstepisthefiling.Twothingsmustbeobserved:thepitchandtheangle.Bypitchismeanttheinclinationoftheteeth.Notetheillustration(Fig.13),whichshowstheteethofaripsaw.YouwillseeatAthatthepitchofthetoothisatrightanglestotheedgeofthesaw.InFig.14,whichshowstheteethofacross-cutsaw,thepitch(B)isabout10degreesoff.Theteethoftheripsawarealsolargerthanthoseofthecross-cut.
THEANGLEOFFILING.--Byangleismeantthecuttingpositionofthefile.InFig.12,thelinesBrepresentthefiledisposedatanangleof12degrees,notmore,foraripsaw.Foracross-cuttheangleofthefilemaybeless.
SAWCLAMPS.--Youmayeasilymakeapairofsawclampsasfollows:
Taketwopiecesofhardwood,eachthreeincheswide,seven-eighthsofaninchthick,andequalinlengthtothelongestsaw.BeveloneedgeofeachasshowninA(Fig.15),soastoleaveanedge(B)aboutone-eighthofaninchthick.Atoneendcutawaythecorneronthesideoppositethebevel,asshownatC,sotheclampswillfitonthesaw
aroundthesawhandle.
[Illustration:_Fig.15._]
Whenthesawisplacedbetweentheseclampsandheldtogetherbythejawsofthevise,youarereadyforthefilingoperation.Observethefollowing_filingsuggestions_:Alwaysholdthefilehorizontalorlevel.Infiling,usethewholelengthofthefile.Dotheworkbyaslow,firmsweep.
Donotfilealloftheteethalongthesawatoneoperation,butonlythealternateteeth,soastokeepthefileatthesameangle,andthusinsureaccuracy;thenturnthesawandkeepthefileconstantlyatone
angleforthealternatesetofteeth.
Givethesamenumberofstrokes,andexertthesamepressureonthefileforeachtooth,toinsureuniformity.Learnalsotomakeafree,easyandstraightmovementbackandforthwiththefile.
THEFILE.--Inordertoexperimentwiththefilingmotion,taketwoblocksofwood,andtrysurfacingthemoffwithafile.Whenyouplacethetwofiledsurfacestogetherafterthefirsttrialbothwillbeconvex,becausethehands,infiling,unlessyouexerttheutmost
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vigilance,willassumeacrank-likemovement.Thefilingtestissotofilethetwoblocksthattheywillfittightlytogetherwithoutrollingoneachother.Beforeshapingandplaningmachineswereinvented,machinistswerecompelledtoplanedownandaccuratelyfinishoffsurfaceswithafile.
Inusingthefilesonsaws,howeversmallthefilemaybe,onehandshouldholdthehandleandtheotherhandthetipofthefile.
Afilebrushshouldalwaysbekeptonhand,asitpaystopreservefilesbycleaningthem.
[Illustration:_Fig.16._]
THEGRINDSTONE.--Asmostofthetoolsrequireagrindstoneforsharpeningpurposes,anillustrationisgivenasaguide,withadiagramtoshowthepropergrindingangle.InFig.16theupright(A)oftheframeservesasalinefortheeye,sothatifthepointofthetoolisbroughttothesightline,andthetool(C)heldlevel,youwillalwaysbeabletomaintainthecorrectangle.Thereisnoobjectiontoprovidingarest,forinstance,likethecrossbars(D,D),buttheartisandisdainssuchcontrivances,andheusuallyavoidsthemfortworeasons:First,becausehabitenableshimtoholdthetoolhorizontally;and,second,byholdingthetoolfirmlyinthehandhehasbetter
controlofit.Thereisonlyonethingwhichcanbesaidinfavorofarest,andthatis,thestonemaybekepttruercircumferentially,asallstoneshavesoftspotsorsides.
INTHEUSEOFGRINDSTONES.--Therearecertainthingstoavoidandtoobserveintheuseofstones.Neveruseonespotonthestone,howevernarrowthetoolmaybe.Alwaysmovethetoolfromsidetoside.Nevergrindasetofnarrowtoolssuccessively.Ifyouhavechiselstogrindinterspersetheirgrindingwithplanebits,hatchetorotherbroadcuttingtools,soastopreventthestonefromhavinggroovestherein.Neveruseatoolonastoneunlessyouhavewaterinthetray.
[Illustration:_Fig.17.Correctmannerofholdingtool._]
[Illustration:_Fig.18.Incorrectwayofholdingtool._]
CORRECTWAYTOHOLDTOOLFORGRINDING.--Thereisacorrectwaytoholdeachtool;seeillustration(Fig.17).Thelefthandshouldgraspthetoolfirmly,nearthesharpedge,asshown,andtherighthandshouldlooselyholdthetoolbehindthelefthand.Thereisareasonforthiswhichwillbeapparentafteryougrindafewtools.Thefirmgraspofthelefthandgivesyouabsolutecontroloftheblade,soitcannotturn,andwheninequalitiesappearinthegrindstone,therigidholdwillpreventthebladefromturning,andthusenableyoutocorrecttheinequalitiesofthestone.Bearinmind,thestoneshouldbetakencareofjustasmuchasthetools.Anexperiencedworkmanisknownbythe
conditionofhistools,andthegrindstoneisthebestfriendhehasamonghistools.
INCORRECTWAYTOHOLDTOOLFORGRINDING.--TheincorrectwayofholdingatoolisshowninFig.18.This,Ipresume,istheuniversalwayinwhichthenovicetakesthetool.Itiswrongforthereasonthatthethumbsofbothhandsareontopoftheblade,andtheyserveaspivotsonwhichthetoolmayturn.Theresultisthatthecornersofthetoolwilldigintothestonetoagreaterorlessdegree,particularlyifithasanarrowblade,likeachisel.
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Trytheexperimentofgrindingaquarter-inchchiselbyholdingittheincorrectway;andthengraspitfirmlywiththelefthand,andyouwillatonceseethedifference.
Thelefthandservesbothasaviseandasafulcrum,whereastherighthandcontrolstheangleofthetool.
[Illustration:_Fig.19._]
Theseremarksapplytoallchisels,planebitsandtoolsofthatcharacter,butitisobviousthatadrawknife,whichisalwaysheldbythehandlesingrinding,andhatchets,axesandthelike,cannotbeheldinthesamemanner.
Atoocommonerroristopressthetooltoohardonthestone.Thisiswrong.Donottrytoforcethegrinding.
Then,again,itisthepracticeofsometoturnthestoneawayfromthetool.Thestoneshouldalwaysmovetowardthetool,soastopreventformingafeatheredge.
THEPLANE.--Indiscriminateuseofplanesshouldbeavoided.Neverusetheforeorsmoothingplanesonroughsurfaces.Thejackplaneisthe
propertoolforthiswork.Ontheotherhand,theforeplaneshouldinvariablybeusedforstraighteningtheedgesofboards,orforfinesurfacingpurposes.Asthejackplanehasitsbitgroundwithacurvededge,itisadmirablyadaptedfortakingofftheroughsawprintsurface.
THEGAGE.--Theillustration(Fig.19)showsoneofthemostusefultoolsinthekit.Itisusedtoscribethethicknessofthematerialwhichistobedresseddown,orforimprintingtheedgesoftenonsandmortises.Twoshouldbeprovidedineverykit,forconvenience.
Thescribingpointshouldbesharpenedwithafile,thepointbeingfiledtoformablade,whichisatrightanglestothebar,orparallel
withthemovablecheekpiece.
CHISELS.--Ihavealreadypointedout,ingeneral,howtoholdtoolsforgrindingpurposes,thisdescriptionapplyingparticularlytochisels,butseveraladditionalthingsmaybeadded.
Alwaysbecarefultogrindthechiselsoitscuttingedgeissquarewiththesideedge.Thiswillbedifficultatfirst,butyouwillseethevalueofthisasyouusethetool.Forinstance,inmakingrebatesforhinges,orrecessesandmortisesforlocks,thetoolwillinvariablyruncrooked,unlessitisgroundsquare.
Thechiselshouldneverbestruckwithahammerormetalinstrument,as
themetalpoleorpeonofthehammerwillsliverthehandle.Thewoodenmalletshouldinvariablybeused.
GENERALOBSERVATIONS.--Iftheworkmanwillcarefullyobservetheforegoingrequirementshewillhavetakenthemostimportantstepsintheknowledgeoftheart.Ifhepermitshimselftocommenceworkwithouthavinghistoolsinfirst-classcondition,heistryingtodoworkundercircumstanceswhereevenaskilledworkmanisliabletofail.
Avoidmakingforyourselfalotofunnecessarywork.Thebestartisans
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arethosewhotrytofindoutandknowwhichisthebesttool,orhowtomakeatoolforeachrequirement,butthattool,tobeserviceable,mustbeproperlymade,andthatmeansitmustberightlysharpened.
CHAPTERIII
HOWTOHOLDANDHANDLETOOLS
Observationmayformpartofeachboy'slesson,butwhenitcomestothehandlingoftools,practicebecomestheonlyavailablemeansofmakingaworkman.Fiftyyearsofobservationwouldnevermakeanobserveranarcheroramarksman,norwoulditenablehimtoshoeahorseortobuildatable.
Itsometimeshappensthatanapprenticewill,withlittleobservation,seizeasawintheproperway,orholdaplaneinthecorrectmanner,and,intime,thewatchfulboywillacquirefairlycorrecthabits.Butwhyputinuselesstimeandlaborinordertogainthatwhichafewwell-directedhintsandexampleswillconvey?
Toolsaremadeandareusedasshortcutstowardadesiredend.Beforethesawwasinventedtheknifewasusedlaboriouslytoseverandshapethematerials.Beforeplaneswereinventedabroad,flatsharpenedbladewasusedtosmoothoffsurfaces.Holesweredugoutbymeansofsmallchiselsrequiringinfinitepatienceandtime.Eachsucceedingtoolproclaimedashorterandaneasierwaytodoacertainthing.Themanorboywhocanmakeanewlabor-savingtoolisworthyofasmuchpraiseasthemanwhomakestwobladesofgrassgrowwhereonegrewbefore.
Letusnowthoroughlyunderstandhowtoholdanduseeachtool.Thatishalfthevalueofthetoolitself.
THESAW.--Withsuchacommonplacearticleasthesaw,itmightbe
assumedthattheordinaryapprenticewouldlookuponinstructionwithasmileofderision.
HOWTOSTARTASAW.--Iftheuntriedapprenticehassuchanopinionsethimtoworkatthetaskofcuttingoffaboardaccuratelyonaline.Hewillgenerallymakeafailureoftheattempttostartthesawtruetotheline,tosaynothingoffollowingthelinesothekerfistrueandsquarewiththeboard.
HOWTOSTARTONALINE.--Thefirstmistakehemakesistosaw_ontheline_.Thisshouldneverbedone.Theworkshouldbesolaidoutthatthesawkerfisonthediscardedsideofthematerial.Thesawshouldcutalongsidetheline,and_thelineshouldnot_beobliteratedinthe
cutting.Materialmustbeleftfortrimmingandfinishing.
THEFIRSTSTROKE.--Now,toholdthesawinstartingisthedifficulttasktothebeginner.Oncemastereditissimpleandeasy.Theonlytimeinwhichthesawshouldbefirmlyheldbythehandisduringtheinitialcutortwo;afterwardsalwaysholdthehandleloosely.Thereisnothingsotiringasatightlygraspedsaw.Thesawhasbutonehandle,henceitisdesignedtobeusedwithonehand.Sometimes,withlongandtiresomejobs,inripping,twohandsmaybeused,butonehandcanalwayscontrolasawbetterthantwohands.
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[Illustration:_Fig.20._]
THESTARTINGCUT.--Inordertomakeourunderstandingofthestartingcutmoreexplicit,werefertoFig.20,inwhichthethumbofthelefthandisshowninthepositionofaguide--theendofthethumbbeingheldupasufficientdistancetocleartheteeth.Inthispositionyouneednotfearthattheteethofthesaw(A)willrideupoverthethumbifyouhaveafirmgraspofthesawhandle.
Thefirststrokeshouldbeupwardly,notdownwardly.Whileintheactofdrawingupthesawyoucanjudgewhetherthesawbladeisheldbythethumbgageintheproperpositiontocutalongthemark,andwhenthesawmovesdownwardlyforthefirstcut,youmaybeassuredthatthecutisaccurate,orattherightplace,andthethumbshouldbekeptinitspositionuntiltwoorthreecutsaremade,andtheworkisthenfairlystarted.
[Illustration:_Fig.21.Wrongsawingangle._]
FORCROSS-CUTTING.--Forordinarycross-cuttingtheangleofthesawshouldbeat45degrees.Forripping,thebestresultsarefoundatlessthan45degrees,butyoushouldavoidflatteningdowntheangle.AnincorrectaswellasacorrectangleareshowninFigs.21and22.
FORCINGASAW.--Forcingasawthroughthewoodmeansacrookedkerf.Themorenearlythesawisheldatrightanglestoaboard,thegreateristheforcewhichmustbeappliedtoitbythehandtocauseittobiteintothewood;and,ontheotherhand,ifthesawislaiddowntoofar,asshownintheincorrectway,itisaverydifficultmattertofollowtheworkingline.Furthermore,itisahardmattertocontrolthesawsothatitwillcutsquarelyalongtheboard,particularlywhenripping.Theeyemustbetheonlyguideinthedispositionofthesaw.Someboysmakethesawruninonedirection,andotherscauseittoleantheoppositeway.Afteryouhavehadsomeexperienceandknowwhichwayyoulean,correctyourhabitsbydisposingthesawintheoppositedirection.
[Illustration:_Fig.22.Rightsawingangle._]
THESTROKE.--Makealongstroke,usingthefullbladeofthesaw.Don'tacquirethe"jerky"styleofsawing.Ifthehandleisheldloosely,andthesawisattheproperangle,theweightofthesaw,togetherwiththeplacementofthehandleonthesawblade,willbefoundsufficienttomaketherequisitecutateachstroke.
Youwillnoticethatthehandleofeverysawismountednearestthebackedge.(SeeFig.23.)Thereasonforsomountingitis,thatasthecuttingstrokeisdownward,thelineofthrustisabovethetoothline,andasthislineisatanangletothelineofthrust,thetendencyis
tocausethesawteethtodigintothewood.
[Illustration:_Fig.23._]
[Illustration:CHINESESAW._Fig.24._]
THECHINESESAW.--Thissawisdesignedtosawwithanupwardcut,andtheillustration(Fig.24)showsthehandlejuttingoutbelowthetoothline,inordertocausetheteethtodigintothematerialasthehandleisdrawnupwardly.Referenceismadetothesefeaturestoimpressupon
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beginnersthevalueofobservation,andtodemonstratethereasonformakingeachtoolaparticularway.
THINGSTOAVOID.--Donotoscillatethesawasyoudrawitbackandforth.Thisisunnecessarywork,andshowsimpatienceintheuseofthetool.Thereissuchaninfinitevarietyofuseforthedifferenttoolsthatthereisnonecessityforrenderingtheworkofanyparticulartool,ortools,burdensome.Eachinitsproperplace,handledintelligently,willbecomeapleasure,aswellasasourceofprofit.
[Illustration:_Fig.25._]
THEPLANE.--Thejackplaneandtheforeplanearehandledwithbothhands,andthesmoothingplanewithonehand,butonlywhenusedfordressingtheendsofboards.Forotherusesbothhandsarerequired.
ANGLESFORHOLDINGPLANES.--Beforecommencingtoplaneaboard,alwaysobservethedirectioninwhichthegrainofthewoodruns.Thisprecautionwillsavemanyapieceofmaterial,becauseifthejackplaneissetdeepitwillrunintothewoodandcausearoughsurface,whichcanbecuredonlybyanextraamountoflaborinplaningdown.
Nevermovethejackplaneorthesmoothingplaneovertheworksothatthebodyofthetoolisinadirectlinewiththemovementoftheplane.
Itshouldbeheldatanangleofabout12or15degrees(seeFig.25).Theforeplaneshouldalwaysbeheldstraightwiththemovementoftheplane,becausethelengthoftheforeplanebodyisusedasastraightenerforthesurfacetobefinished.
[Illustration:_Fig.26._]
ERRORSTOBEAVOIDED.--Neverdrawbacktheplanewiththebitrestingontheboard.Thissimplywearsoutthetool,andifthereshouldbeanygritontheboarditwillbesuretoruinthebit.Thisappliesparticularlytothejackplane,butisbadpracticewiththeothersaswell.
Aworkbenchisareceptacleforallkindsofdirt.Provideaspecialledgeorshelffortheplanes,andbesuretoputeachplanethereimmediatelyafterusing.
THEGAGE.--Aman,whoprofessedtobeacarpenter,oncetoldmethatheneverusedagagebecausehecouldnotmakeitrunstraight.Afewmoments'practiceconvincedhimthatheneverknewhowtoholdit.Theillustrationshowshowproperlytoholdit,andthereasonwhyitshouldsobeheldfollows.
Youwillobserve(Fig.26)thatthehandgraspsthestemofthegagebehindthecheekpiece,sothatthethumbisfreetopressagainstthesideofthestemtothefrontofthecheekpiece.
HOLDINGTHEGAGE.--Thehandservestokeepthecheekpieceagainsttheboard,whilethethumbpushesthegageforward.Thehandmustnot,underanycircumstances,beusedtomovethegagealong.Infact,itisnotnecessaryforthefingerstobeclaspedaroundthegagestem,iftheforefingerpressestightlyagainstthecheekpiece,sincethethumbperformsalltheoperationofmovingitalong.Naturally,thehandgraspsthetoolinordertoholditdownagainstthematerial,andtobringitbackforanewcut.
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THEDRAW-KNIFE.--Itisdifficultfortheapprenticetobecomeaccustomedtohandlethisusefultool.Itismuchmoreserviceablethanahatchetfortrimmingandparingwork.Inapplyingittothewoodalwayshavethetoolatananglewiththeboard,soastomakeaslicingcut.Thisisspeciallydesirableinworkingclosetoaline,otherwisethereisaliabilityofcuttingoverit.
Thiskniferequiresafirmgrasp--firmnessofholdismoreimportantthanstrengthinusing.Theflatsideisusedwhollyforstraightedges,andthebeveledsideforconcavesurfaces.Itistheintermediatetoolbetweenthehatchetandtheplane,asithasthecharacteristicsofboththosetools.Itisanugly,dangeroustool,moretobefearedwhenlyingaroundthanwheninuse.Putitreligiouslyonarackwhichprotectstheentirecuttingedge._Keepitoffthebench._
CHAPTERIV
HOWTODESIGNARTICLES
FUNDAMENTALSOFDESIGNING.--Agreatdealofthepleasureinmaking
articlesconsistsincreativework.Thismeans,notthatyoushalldesignsomeentirelynewarticle,butthatitsgeneralform,orarrangementofparts,shallhavesomeneworstrikingfeature.
Anewdesigninanyartdoesnotrequireachangeinallitsparts.Itissufficientthatthereshallbeanimprovement,eitherinsomeparticularpoint,asamatterofutility,orsomechangeinanartisticdirection.Amanufacturerinputtingoutanewchair,oraplow,oranautomobile,addssomestrikingcharacteristic.Thisbecomeshistalkingpointinsellingthearticle.
THECOMMERCIALINSTINCT.--Itisnotenoughthattheboyshouldlearntomakethingscorrectly,andasamatterofpastimeandpleasure.The
commercialinstinctis,afterall,thegreatincentive,andshouldbegivendueconsideration.
Itwouldbeimpossible,inabookofthiskind,todomorethantogivethefundamentalprinciplesnecessaryindesigning,andtodirectthemindsolelytoessentials,leavingtheindividualtobuildupforhimself.
FIRSTREQUIREMENTSFORDESIGNING.--First,then,letusseewhatisnecessarytodowhenyouintendtosetaboutmakinganarticle.Supposewefixourmindsuponatableasthearticleselected.Threethingsarenecessarytoknow:First,theusetowhichitistobeput;second,thedimensions;and,third,thematerialrequired.
Assumingittobetheordinarytable,andthedimensionsfixed,wemayconcludetousesoftpine,birchorpoplar,becauseofeaseinworking.Therearenoregulationdimensionsfortables,exceptastoheight,whichisgenerallyuniform,andusually30inches.Astothelengthandwidth,youwillbegovernedbytheplacewhereitistobeused.
Ifthetabletopistohavedimensions,say,of36"48",youmaylayouttheframeworksixincheslesseachway,thusgivingyouatopoverhangofthreeinches,whichistheusualpractice.
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CONVENTIONALSTYLES.--Now,ifyouwishtodepartfromtheconventionalstyleofmakingatableyoumaymakevariationsinthedesign.Forinstance,theChippendalestylemeansslenderlegsandthintop.Itinvolvessomefancifuldesignsinthecurvedoutlinesofthetop,andinthecrookofthelegs.Orif,ontheotherhand,theMissiontypeispreferred,theoverhangofthetopisverynarrow;thelegsarestraightandheavy,andofevensizefromtoptobottom;andthetabletopisthickandnearlyasbroadasitislong.Suchfurniturehastheappearanceofmassiveness;itiseasilymadeandmostserviceable.
MISSIONSTYLE.--TheMissionstyleofarchitecturealsolendsitselftothemakingofchairsandotherarticlesoffurniture.Achairis,probably,themostdifficultpieceofhouseholdfurnituretomake,becausestrengthisrequired.Inthistypesoftwoodmaybeused,asthelargelegsandbackpiecesareeasilyprovidedwithmortisesandtenons,affordinggreatrigiditywhencompleted.Indesigning,therefore,youmayseehowthematerialitselfbecomesanimportantfactor.
CABINETS.--Inthemakingofcabinets,sideboards,dressersandlikearticles,theingeniousboywillfindawonderfulfieldfordesigningability,becauseinthesearticlesfancyalonedictatesthesizesandthedimensionsoftheparts.Notsowithchairsandtables.Theimaginationplaysanimportantparteveninthemakingofdrawers,to
saynothingofplacingthemwithaneyetoconvenienceandartisticeffect.
HARMONYOFPARTS.--Butonethingshouldbeobservedinthemakingoffurniture,namely,harmonybetweentheparts.Forinstance,atablewiththinlegsandathicktopgivestheappearanceofatop-heavystructure;orthewronguseoftwodifferentstylesisbadfromanartisticstandpoint;moreover,itistheheightofrefinededucationif,intheuseofcontrastingwoods,theyareproperlyblendedtoformaharmoniouswhole.
HARMONIZINGWOOD.--Imagineachiffonierwiththebaseofdarkwood,likewalnut,andthetopofpineormaple,oralikelight-coloredwood.On
theotherhand,bothwalnutandmaple,forinstance,maybeusedinthesamearticle,iftheyareinterspersedthroughouttheentirearticle.Thebodymaybemadeofdarkwoodandtrimmedthroughoutwithalightwoodtoproduceafineeffect.
CHAPTERV
HOWWORKISLAIDOUT
CONCRETEEXAMPLESOFWORK.--Aconcreteexampleofdoinganyworkismorevaluablethananabstractstatement.ForthispurposeIshalldirectthebuildingofacommontablewithadrawerinitandshowhowtheworkisdoneindetail.
ForconvenienceletusadopttheMissionstyle,withatop36"42"andtheheight30".Thelegsshouldbe2"2"andthetop1",dressed.Thematerialshouldbeofhardwoodwithnaturalfinish,or,whatisbetterstill,asoftwood,likebirch,whichmaybestainedadarkbrown,astheMissionstyleismoreeffectiveindarkthaninlightwoods.
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[Illustration:_Fig.27._]
FRAMEWORK.--Aswenowknowthesizes,thefirstthingistobuildtheframework.Thelegsshouldbedressedsquareandsmootheddownwiththeforeplanetomakethemperfectlystraight.Now,layouttwomortisesattheupperendofeachleg.Followtheillustrationstoseehowthisisdone.
LAYINGOUTTHELEGS.--Fig.27showsalegwithsquarecrossmarks(A)ateachend.Thesemarksindicatethefinishedlengthoftheleg.Youwillalsoseecrossesontwosides.Theseindicatewhatiscalledthe"worksides."Theworksidesareselectedbecausetheyarethefinestsurfacesontheleg.
[Illustration:_Fig.28._]
[Illustration:_Fig.29._]
THELENGTHOFTHEMORTISES.--Thentakeasmalltrysquare(Fig.28)andaddtwocrosslines(B,C)oneachoftheinnersurfaces,thesecondline(B)one-halfinchfromthefinishline(A),andtheotherline(C)seveninchesdownfromtheline(A).Thesidefacingboards,hereafterdescribed,aresevenincheswide.
Whenthishasbeendoneforallthelegs,prepareyourgage(Fig.29)tomakethemortisescribe,and,forconvenienceinillustrating,thelegisreversed.Ifthefacingboardsare1"thick,andthetenonsareintendedtobe1/2"thick,thefirstscribeline(E)shouldbe1/2"fromtheworkside,becausetheshoulderonthefacingboardprojectsout1/4",andtheoutersurfaceofthefacingboardshouldnotbeflushwiththeoutersurfaceoftheleg.Thesecondgageline(F)shouldbe1"fromtheworkside.
[Illustration:_Fig.30._]
THEMORTISES.--Whenthemortiseshavebeenmadetheywillappearas
shownintheenlargedcrosssectionoftheleg(Fig.30),thetotaldepthofeachmortisebeing1-1/2".Thedepthofthismortisedeterminesforusthelengthofthetenonsonthefacingboards.
THEFACINGBOARDS.--Theseboardsareeach1inchthickand7incheswide.Asthetopofthetableis42incheslong,andwemustprovideanoverhang,sayof2inches,wewillfirsttakeoff4inchesfortheoverhangand4inchesforthelegs,sothatthelengthoftwoofthefacingboards,fromshouldertoshoulder,mustbe34inches;andtheothertwofacingboards28inches.Then,aswemustadd1-1/2inchesforeachtenon,twooftheboardswillbe37incheslongandtwoofthem31incheslong.
[Illustration:_Fig.31._]
[Illustration:_Fig.32._]
Theillustration(Fig.31)showsaboardmarkedwiththecrosslines(B)ateachendfortheendofthetenons,ortheextremeendsoftheboards.
THETENONS.--Donotneglectfirsttoselecttheworksideandtheworkingedgeoftheboard.Theoutersurfaceandtheupperedgesarethe
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sidestoworkfrom.Thecheekpiece(A)ofthegagemustalwaysrestagainsttheworkingside.
Thecrossmarks(B,C)shouldbemadewiththepointofasharpknife,andbeforethesmallbacksawisusedonthecross-cutsthelines(B),whichindicatetheshoulders,shouldbescoredwithasharpknife,asshowninFig.33.Thisfurnishesaguideforthesaw,andmakesaneatfinishfortheshoulder.
[Illustration:_Fig.33._]
[Illustration:_Fig.34._]
[Illusstration_Fig.35._]
TOOLSUSED.--Thebacksawisusedforcuttingthetenon,andtheendoftheboardappearsasshownintheenlargedFig.34.Twothingsarenownecessarytocompletethetenons.Ontheupperorworkedgeofeachboardusethegagetomarkoffahalf-inchslice,andthencutawaytheflatsideofthetenonattheend,onitsinnersurface,soitwillappearasshowninFig.35.
[Illustration:_Fig.36._]
[Illustration:_Fig.37._]CHAMFEREDTENONS.--Theobjectofthesechamferedorbeveledtenonsistopermittheendstoapproacheachothercloselywithinthemortise,asshownintheassembledparts(Fig.36).
THEFRAMEASSEMBLED.--Theframeisnowreadytoassemble,butbeforedoingsoadraweropeningandsupportsshouldbemade.Theendsofthesupportsmaybemortisedintothesidepiecesorsecuredbymeansofgains.
Mortisesandtenonsarebetter.
THEDRAWERSUPPORTS.--Takeoneoftheside-facingboards(Fig.37)andcutarectangularopeninginit.Thisopeningshouldbe4incheswideand18incheslong,soplacedthatthereis1inchofstockattheuppermarginand2inchesofstockatthelowermarginoftheboard.Ateachlowercornermakeamortise(A),sothatonesideofthemortiseisonalinewiththemarginoftheopening,andsothatitextendsahalfinchpasttheverticalmarginoftheopening.
[Illustration:_Fig.38._]
Youcaneasilycutagain(B)inastrip,or,asinFig.38,youmayusetwostrips,one(C)aninchwideandahalfinchthick,andonthisnailastrip(D)alongonemargin.Thisformstheguideandrestforthe
drawer.
Attheuppermarginoftheopeningisarebateorgain(E)ateachcorner,extendingdowntothetoplineofthedraweropening,intowhicharefittedtheendsoftheuppercrossguides.
THETABLEFRAME.--WhentheentiretableframeisassembleditwillhavetheappearanceshowninFig.39,anditisnowreadyforthetop.
THETOP.--Thetopshouldbemadeofthreeboards,eithertonguedand
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grooved,ordoweledandgluedtogether.Inordertogiveamassiveappearance,andalsotopreventtheendgrainoftheboardsfrombeingexposed,beveledstripsmaybeusedtoencasetheedges.Thesemarginalcleatsare3/4inchthickand2incheswide,andjoinedbybeveledendsatthecorners,asshowninFig.40.
[Illustration:_Fig.39._]
THEDRAWER.--Thedrawer(Fig.41)shownincrosssection,hasitsfront(A)providedwithanoverlappingflange(B).
Itisnotourobjectinthischaptertoshowhoweachparticulararticleismade,butsimplytopointouttheunderlyingprinciples,andtoillustratehowthefasteningelements,thetenonsandmortises,areformed,sothattheboywillknowtheproperstepsintheirnaturalorder.
[Illustration:_Fig.40._]
HOWANYSTRUCTUREISBUILTUP.--Itshouldbeobservedthateachstructure,howeversmall,isusuallybuiltfromthebaseup.Justthesameasthemorepretentiousbuildingsareerected:First,thesill,thenthefloorsupports,thenthepostsandtopplates,withtheirconnectinggirders,and,finally,theroof.
ThechapteronHouseBuildingwillgivemoredetailedillustrationsoflargestructures,andhowtheyareframedandbraced.Atthispointwearemoreconcernedinknowinghowtoproceedinordertolayoutthesimplestructuraldetails,andifonesubjectofthiskindisfullymasteredthecomplicatedcharacterofthearticlewillnotbedifficulttomaster.
OBSERVATIONSABOUTABOX.--Assimplealittlearticleasaboxfrequentlybecomesaburdentoabeginner.Tryit.Simplykeepinmindonething;eachboxhassixsides.Now,supposeyouwantaboxwithsixequalsides--thatis,acubicalform--itisnecessarytomakeonlythreepairsofsides;twofortheends,twoforthesidesandtwoforthetop
andbottom.Eachsethasdimensionsdifferentfromtheothersets.Bothpiecesoftheset,representingtheends,aresquare;thesidepiecesareofthesamewidthastheendpieces,andslightlylonger;andthetopandbottomarelongerandwiderthantheendpieces.
[Illustration:_Fig.41._]
Aboxequalinallitsdimensionsmaybemadeoutofsixboards,properlycut.Makeanattemptinordertoseeifyoucangettherightdimensions.
JOINTS.--Forjoiningtogetherboardsatrightanglestoeachother,suchasboxcorners,drawersandlikearticles,tenonsandmortisesshould
neverberesortedto.Inordertomakefineworkthejointsshouldbemadebymeansofdovetails,rabbetsorrebates,orbybevelingormiteringtheends.
BEVELINGANDMITERING.--Thereisadifferenceintheterms"beveling"and"mitering,"asusedintheart.InFig.42thejointAis_beveled_,andinFig.43thejointBis_mitered_,thedifferencebeingthatabevelisappliedtoananglejointlikeaboxcorner,whileamiterhasreferencetoajointsuchasisillustratedinFig.43,suchasthecornerofapictureframe.
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[Illustration:_Fig.42._]
[Illustration:_Fig.43._]
PROPERTERMS.--Itistheapplicationofthecorrecttermstothingsthatlaysthefoundationforaccuratethinkingandproperexpressionsindescribingwork.Awisemanoncesaidthatthebasisoftruescienceconsistsincorrectdefinitions.
PICTUREFRAMES.--Inpictureframesthemiteredcornersmayhaveasawkerf(C)cutacrossthecorners,asshowninFig.44,andathinbladeofhardwooddrivenin,thewholebeinggluedtogether.
DOVETAILJOINTS.--Itisinthelayingoutofthemorecomplicateddovetailjointsthatthehighestskillisrequired,becauseexactnessisofmoreimportanceinthisworkthaninanyotherarticleinjoinery.Inordertodothisworkaccuratelyfollowouttheexamplesgiven,andyouwillsoonbeabletomakeabeautifuldovetailcorner,anddoitquickly.
[Illustration:_Fig.44._]
PREPARINGABOXJOINT.--Inordertomatchaboxjointfortheinnerend
ofatabledrawer,thefirststepistoselecttwoworksides.Oneworksidewillbetheedgeoftheboard,andtheotherthesidesurfaceoftheboard,andonthosesurfaceswewillputcrosses,asheretoforesuggested.
[Illustration:_Fig.45._]
[Illustration:_Fig.46._]
[Illustration:_Fig.47._]
FIRSTSTEPS.--Nowlaptogethertheinnersurfacesoftheseboards(Y,Z),sotheendsaretowardyou,asshowninFig.45.Then,after
measuringthethicknessoftheboardstobejoined(thethinnest,iftheyareofdifferentthicknesses),setyourcompasses,ordividers,for1/4inch,providingtheboardsare1/2inchthick,and,commencingattheworkedgeoftheboard,stepoffandpoint,asatA,thewholewidthoftheboard,andwithasquaremakethetwocrossmarks(B),usingthetwofirstcompasspoints(A),thenskippingone,usingthenexttwo,andsoon.
[Illustration:_Fig.48._]
[Illustration:_Fig.49._]
[Illustration:_Fig.50._]
Whenthisisdone,turnuptheboardZ(Fig.46),sothatitisatrightanglestotheboardY,andsotheoutersurfaceoftheboardZisflushwiththeendoftheboardX,andwithasharpknifepointextendthelinesBalongwiththegrainofthewoodonboardZ,uptothecrossmarkC.ThiscrossmarkshouldhavebeenpreviouslymadeandislocatedasfarfromtheendoftheboardZasthethicknessoftheboardY.
WenowhavethemarksfortheoutersurfaceoftheboardZ,andtheendmarksofboardY.Forthepurposeofgettingtheanglesoftheendof
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theboardZandtheoutersideofboardY,acrossline(D,Fig.47)isdrawnacrosstheboardXneartheend,thislinebeingasfarfromtheendasthethicknessoftheboardZ,andaverticalline(E)isdrawnmidwaybetweenthetwofirstcrossmarks(A).
Now,withyourcompass,which,inthemeantime,hasnotbeenchanged,makeamark(F),anddrawdowntheline(G),whichwillgiveyoutheworkingangleatwhichyoumaysetthebevelgage.Thendrawdownananglefromeachalternatecrossline(A),andturnthebevelanddrawdownthelines(H).Theselinesshouldallbeproducedontheoppositesideoftheboard,soastoassureaccuracy,andtothisendtheedgesoftheboardalsoshouldbescribed.
CUTTINGOUTTHESPACES.--Incuttingouttheinterveningspaces,whichshouldbedonewithasharpchisel,careshouldbeobservednottocutovertheshoulderlines.Topreventmistakesyoushouldputsomedistinctivemarkoneachparttobecutaway.InthisinstanceE,Hshowthepartstoberemoved,andinFig.48twoofthecutawayportionsareindicated.
WhentheendoftheboardZisturnedup(Fig.49),ithasmerelythelongitudinalparallellinesB.ThebevelsquaremaynowbeusedinthesamemannerasonthesideoftheboardY,andthefittingangleswillthenbeaccuratelytrue.
ThisisshowninFig.50,inwhich,also,twoofthecutawaypartsareremoved.
TOOLSUSEDINLAYINGOUTTENONSANDMORTISES.--Asharp-pointedknifemustalwaysbeusedformakingallmarks.Neveremployanawlforthiswork,asthefiberofthewoodwillbetornupbyit.Asmalltrysquareshouldalwaysbeused(notthelargeironsquare),andthiswithasharp-pointedcompassandbevelsquarewillenableyoutoturnoutasatisfactorypieceofwork.
Theforegoingexamples,carefullystudied,willenableyoutogathertheprinciplesinvolvedinlayingoffanywork.Ifyoucanoncemakea
presentableboxjoint,sothatallthedovetailswillaccuratelyfittogether,youwillhaveaccomplishedoneofthemostdifficultphasesofthework,anditisanexercisewhichwillamplyrepayyou,becauseyouwilllearntoappreciatewhataccuracymeans.
CHAPTERVI
THEUSESOFTHECOMPASSANDTHESQUARE
THESQUARE.--Thesquareis,probably,theoldestofalltools,andthat,togetherwiththecompass,ordividers,withwhichthesquareisalwaysassociated,hasconstitutedthecraftsman'semblemfromtheearliesthistoricaltimes.Sofaraswenowknow,theplainflatform,whichhasatleastonerightangleandtwoormorestraightedges,wastheonlyformofsquareusedbytheworkman.Butmodernuses,andthedevelopmentofjoineryandcabinetmaking,aswellasthemoreadvancedformsofmachinerypractice,necessitatednewstructuralformsinthesquare,sothatthebevelsquare,inwhichthereisanadjustablebladesetinahandle,wasfoundnecessary.
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THETRYSQUARE.--Intheuseoftheordinarylargemetalsquareitisnecessarytolaytheshortlimbofthesquareonthefaceofthework,andthelonglimbmust,therefore,restagainsttheworksideoredgeofthetimber,sothatthescribingedgeoftheshortlimbdoesnotrestflatagainstthework.Assuchatoolisdefectiveinworkrequiringaccuracy,itbroughtintoexistencewhatiscalledthetrysquare,whichhasarectangularhandle,usuallyofwood,intowhichisfittedatoneendametalblade,whichisatrightanglestotheedgeofthehandle.Thehandle,therefore,alwaysservesasaguideforthebladeinscribingwork,becauseitliesflatdownonthework.
THET-SQUAREisanothermodificationofthetrysquare,itsprincipalusebeingfordraughtingpurposes.
THECOMPASS.--Thecompassisoneoftheoriginalcarpenter'stools.Thedifferencebetween_compass_and_dividers_isthatcompasseshaveadjustablepenorpencilpoints,whereasdividersarewithoutadjustablepoints.Modernworkhasbroughtrefinementsinthecharacterofthecompassanddividers,sothatwenowhavethebow-compass,whichis,usually,asmalltool,onelegofwhichcarriesapenorpencilpoint,thetwolegsbeingsecuredtogether,usually,byaspringbow,orbyahingedjointwithaspringattachment.
PROPORTIONALDIVIDERS.--Ausefultooliscalledtheproportionaldividers,thelegsofwhicharehingedtogetherintermediatetheends,sothatthepivotaljointisadjustable.Bymeansofthistoolthescaleofworkmaybechanged,althoughitswidestfieldofusefulnessisworklaidoffonascalewhichyouintendtoreduceorenlargeproportionally.
DETERMININGANGLES.--Now,inordertolayoutworktheboyshouldknowquicklyandaccuratelyhowtodeterminevariousanglesusedorrequiredinhiswork.Thequickestwayinwhichtolearnthisistobecomefamiliarwiththedegreeinitsvariousrelations.
[Illustration:_Fig.51._]
DEFINITIONOFDEGREE.--Adegreeisnotameasure,aswewoulddesignateafootorapoundtodeterminedistanceorquantity.Itisusedtodenoteadivision,space,intervalorposition.Toillustrate,lookatthecircle,Fig.51.Thefourcardinalpointsareformedbythecrosslines(A,B),andineachoneofthequadrantsthusformedthecircleisdividedinto90degrees.Lookattheradiallines(C,D),andyouwillfindthatthedistancebetweentheselinesisdifferentalongthecurvedline(E)thanalongthecurvedline(F).Thedegreeis,therefore,toindicateonlythespace,divisionorintervalinthecircle.
THEMOSTIMPORTANTANGLE.--Mostimportantforonetoknowataglanceis
thatof45degrees,becausetheonecanthemorereadilycalculatetheotherdegrees,approximately,byhaving45degreesoncefixedinthemind,andimpressedonthevisualimage.Withasquareandacompassitisacomparativelyeasymatteraccuratelytostepoff45degrees,asitisthelineC,midwaybetweenAandB,andtheotherdegreesmaybecalculatedfromthelineCandthecardinallinesAorB.
DEGREESWITHOUTACOMPASS.--Butintheabsenceofacompassandwhenyoudonotwishtostepoffacircle,youwillinsuchcaselaydownthesquare,andmarkoffattheoutermarginofthelimbstwoequal
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Furthermore,andforthisveryreason,youshouldstudytofindouthowtoexplainortodefinetheterms.Youmayhaveamentalpictureofthestructureinyourmind,butwhenaskedtoexplainityouarelost.
LEARNINGMECHANICALFORMS.--Suppose,forexample,wetakethewords_segment_and_sector_.Withoutathoroughunderstandinginyourownmindyouarelikelytoconfusethesetermsbytakingonefortheother.Butletusassumeyouaretobecalledupontoexplainasectortosomeonewhohasnoideaoftermsandtheirdefinitions.Howwouldyoudescribeit?Whileitistrueitiswedge-shaped,youwillseebyexaminingthedrawingthatitisnotlikeawedge.Thesectorhastwosidesrunningfromapointlikeawedge,butthelargeendofthesectoriscurved.
Ifyouwerecalledupontodefineasegmentyoumightsayithadonestraightlineandonecurve,butthiswouldnotdefineitverylucidly.Therefore,ingoingoverthedesignationsgiven,notonlyfixinyourmindtheparticularform,buttrytoremembersomeparticularmannerinwhichyoucanclearlyexpresstheform,theshapeortherelationoftheparts.
Foryourguidance,therefore,Ihavegiven,asfaraspossible,simplefigurestoaidyouinbecomingacquaintedwithstructuresandtheirdesignations,withoutrepeatingthemoresimpleformswhichIhaveused
intheprecedingchapters.[Illustration:_Fig.55.-Fig.65._]
55._Arcade._--Aseriesofarcheswiththecolumnsorpierswhichsupportthem,thespandrelsabove,andotherparts.
56._Arch._--Acurvedmembermadeup,usually,ofseparatewedge-shapedsolids,A.K,Keystone;S,Springers;C,Chord,orspan.
57._Buttress._--Aprojectingmassofmasonry.A,usedforresistingthethrustofanarch,orforornamentation;B,aflyingbuttress.
58._Chamfer._--ThesurfaceAformedbycuttingawaythearrisorangleformedbytwofaces,B,C,ofmaterial.
59._CotterorCotterPin._--Apin,A,eitherflat,squareorround,driventhroughaprojectingtonguetoholditinposition.
60._Crenelated._--Aformofmoldingindentedornotched,eitherregularlyorirregularly.
61._Crosses._--1.Latincross,intheChurchofRomecarriedbeforeBishops.2.Doublecross,carriedbeforeCardinalsandBishops.3.TripleorPapalcross.4.St.Andrew'sandSt.Peter'scross.5.Maltesecross.6.St.AnthonyorEgyptiancross.7.CrossofJerusalem.8.A
crosspattorferm(headorfirst).9.Acrosspatonce(thatis,growinglargerattheends).10.Greekcross.
62._CurbRoof._--Aroofhavingadoubleslope,orcomposedoneachsideoftwopartswhichhaveunequalinclinations;agambrelroof.
63._Cupola._--Socalledonaccountofitsresemblancetoacup.Aroofhavingaroundedform.Whenonalargescaleitiscalledadome.
_CrownPost._--See_KingPost_.
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64._Console._--Abracketwithaprojectionnotmorethanhalfitsheight.
65._Corbels._--Amassofbracketstosupportashelforstructure.LargelyemployedinGothicarchitecture.
[Illustration:_Fig.66.-Fig.79._]
66._Dormer._--Awindowpiercedinaroofandsosetastobevertical,whiletheroofslopesawayfromit.Alsocalleda_Gablet_.
67._Dowel._--Apinorstudinoneblock,orbody,designedtoengagewithholesinanotherbodytoholdthemtogetherinalignment.
68._Drip._--ThatpartofacorniceorsillcourseA,orotherhorizontalmemberwhichprojectsbeyondtherest,soastodivertwater.
69._Detents._--Recessestolockortoserveasastoporholdingplace.
70._Extrados._--Theexteriorcurveofanarch,especiallytheuppercurvedfaceA.Bisthe_Intrados_or_Soffit_.
71._Engrailed._--Indentedwithsmallconcavecurves,astheedgeofa
bordure,bend,orthelike.72._Facet._--Thenarrowplainsurface,asA,betweentheflutingofacolumn.
73._Fret,Fretwork._--Ornamentalworkconsistingofsmallfillets,orslats,intersectingeachotherorbentatrightangles.Openworkinrelief,whenelaboratedandminuteinallitsparts.Henceanyminuteplayoflightandshade.A,Japanesefretwork.B,Greenfret.
74._Frontal_,alsocalled_Pediment_.--Thetriangularspace,A,aboveadoororwindow.
75._Frustums._--Thatpartofasolidnextthebase,formedbycuttingoffthetop;orthepartofanysolid,asofacone,pyramid,etc.,betweentwoplanes,whichmayeitherbeparallelorinclinedtoeachother.
76._Fylfat._--Arebatedcrossusedasasecretemblemandwornasanornament.Itisalsocalled_Gammadium_,andmorecommonlyknownas_Swastika_.
77._GambrelRoof._--Acurbroofhavingthesamesectioninallitsparts,withalower,steeperandlongerpart.See_CurbRoof_anddistinguishdifference.
78._Gargoyle._--Aspoutprojectingfromtheroofgutterofabuilding,oftencarvedgrotesquely.
79._Gudgeon._--Awoodenshaft,A,withasocket,B,intowhichisfittedacasting,C.Thecastinghasa_gudgeon_,D.
[Illustration:_Fig.80.-Fig.93._]
80._Guilloche._--Anornamentintheformoftwoormorebandsorstringstwistedtogetheroroverorthrougheachother.
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81._HalfTimbered._--Constructedofatimberframe,havingthespacesfilledinwithmasonry.
82._HammerBeam._--Amemberofonedescriptionofrooftruss,calledhammer-beamtruss,whichissoframedasnottohaveatiebeamatthetopofthewall.Aisthe_hammerbeam_,andCthependantpost.
83._Haunches._--ThepartsA,A,oneachsideofthecrownofanarch.Eachhaunchisfromone-halftotwo-thirdsofthehalfarch.
84._Header._--Apieceoftimber,A,fittedbetweentwotrimmers,B,B,toholdtheendsofthetailbeams,C,C.
85._HipRoof._--Theexternalangleformedbythemeetingoftwoslopingsidesorskirtsofaroofwhichhavetheirwallplatesrunningindifferentdirections.
86._HoodMolding._--Aprojectingmoldingovertheheadofanarch,asatA,formingtheouter-mostmemberofthearchivolt.
87._Inclave._--Theborder,orborders,havingaseriesofdovetails.Onevariationofmoldingorornamentation.
88._InterlacingArch._--Arches,usuallycircular,soconstructedthattheirarchivolts,A,intersectandseemtobeinterlaced.
89._Invected._--Havingaborderoroutlinecomposedofsemicirclesorarches,withtheconvexityoutward.Theoppositeofengrailed.
90._InvertedArch._--Anarchplacedwiththecrowndownward;usedinfoundationwork.
91._Keystone._--Thecentralortopmoststone,A,ofanarch,sometimesdecoratedwithacarving.
92._KingPost._--Amember,A,ofacommonformoftrussforroofs.It
isstrictlyatieintendedtopreventthesaggingofthetiebeam,B,inthemiddle.Iftherearestruts,C,supportingtherafters,D,theyextenddowntothefootofthe_KingPost_.
93._Label._--Thenamegiventotheprojectingmolding,A,aroundthetopofthedooropening.Aformofmedivalarchitecture.
[Illustration:_Fig.94.-Fig.104._]
94._Louver._--Theslopingboards,A,settoshedrainwateroutwardinanopeningofaframe,asinbelfrywindows.
95._Lintel._--Ahorizontalmember.Aspanningoropeningofaframe,
anddesignedtocarrythewallaboveit.
96._Lug._--A.projectingpiece,asA,towhichanythingisattached,oragainstwhichanotherpart,likeB,isheld.
97._M-Roof._--Akindofroofformedbythejunctionoftwocommonroofswithavalleybetweenthem,sothesectionresemblestheletterM.
98._MansardRoof._--Ahippedcurbroof,thatis,aroofhavingonallsidestwoslopes,thelowerone,A,beingsteeperthantheupperportion
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ordeck.
99._NewelPost._--Theuprightpostatthefootofastairway,towhichtherailingisattached.
100._Parquetry._--Aspeciesofjoineryorcabinetwork,consistingofaninlayofgeometricorotherpatterns,generallyofdifferentcoloredwoods,usedparticularlyforfloors.
101._Peen._also_Pein._--Theround,_round_-edgedorhemisphericalend,asatA,ofahammer.
102._Pendant._--Ahangingornamentonroofs,ceilings,etc.,andmuchusedinthelaterstylesofGothicarchitecturewhereitisofstone.Imitatedlargelyinwoodandplasterwork.
103._Pentastyle._--Apillar.Aporticohavingfivepillars,A,iscalledthe_Pentastyle_intemplesofclassicalconstruction.
104._Pedestal._--Anuprightarchitecturalmember,A,right-angledinplan,constructionallyapier,butresemblingacolumn,havingacapital,shaftandbasetoagreewiththecolumnsinthestructure.
[Illustration:_Fig.105.-Fig.117._]
105._Pintle._--Anuprightpivotpin,orthepinofahinge;Arepresentsthe_pintle_ofarudder.
106._Portico._--Acolonnadeorcoveredstructure,especiallyinclassicalstyle,ofarchitecture,andusuallyattheentranceofabuilding.
107._Plate._--Ahorizontaltimber,A,usedasatoporheaderforsupportingtimbers,roofsandthelike.
108._QueenPost._--Oneoftwosuspendingpostsinarooftruss,orotherframedtrussofsimpleform.Comparewith_KingPost._A,B,tie
beam;C,C,queenposts;D,strainingpiece;E,principalrafter;F,rafter.
109._QuirkMolding._--Asmallchannel,deeplyrecessed,inproportiontoitswidth,usedtoinsulateandgiverelieftoaconvexroundedmolding.Anexcellentcornerpostforfurniture.
110._Re-entering._--Thefigureshowsanirregularpolygon(thatis,many-sidedfigure)andisare-enteringpolygon.TherecessAisare-enteringangle.
111._Rafter._--Originallyanyroughandheavypieceoftimber,butinmoderncarpentryusedtodesignatethemainroofsupport,asatA.See
_QueenPost_.
112._Scarfing._--Cuttingtimberatananglealongitslength,asthelineA.Scarfingjointsarevariouslymade.TheoverlappingjointsmaybestraightorrecessedandprovidedwithakeyblockB.Whenfittedtogethertheyaresecurelyheldbyplatesandbolts.
113._ScotiaMolding._--Asunkenmoldinginthebaseofapillar,socalledfromthedarkshadowwhichitcasts.
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114._Sill._--Incarpentrythebasepiece,orpieces,A,onwhichthepostsofastructureareset.
115._Skew-Back._--Thecourseofmasonry,suchasastone,A,withaninclinedface,whichformstheabutmentforthevoussoirs,B,orwedge-shapedstonescomprisingthearch.
116._Spandrel._--Theirregular,triangularspace,A,betweenthecurveofanarchandtheenclosingrightangle.
117._Strut._--Ingeneral,anypieceofaframe,suchasatimberA,orabraceB,whichresistspressureorthrustinthedirectionofitslength.
[Illustration:_Fig.118.-Fig.123._]
118._Stud,Studding._--Theverticaltimberorscantling,A,whichisoneofthesmalluprightsofabuildingtowhichtheboardingorplasteringlatharenailed.
119._Stile._--Themainuprightsofadoor,asA,A;B,B,B,rails;C,C,mullions;D,D,panels.
_TieBeam._--See_QueenPost_.
120._Trammel._--Averyusefultoolfordrawingellipses.Itcomprisesacross,A,withgroovesandabar,B,withpins,C,attachedtoslidingblocksinthegrooves,andapenorstylus,D,attheprojectingendofthebartoscribetheellipse.
121._Turret._--Alittletower,frequentlyonlyanornamentalstructureatoneoftheanglesofalargerstructure.
122._Transom._--Ahorizontalcross-bar,A,aboveadoororwindoworbetweenadoorandawindowaboveit.Transomisthehorizontalmember,andifthereisavertical,likethedottedlineB,itiscalleda_Mullion_.See_Stile_.
123._ValleyRoof._--Aplaceofmeetingoftwoslopesofaroofwhichhavetheirsidesrunningindifferentdirectionsandformedontheplanofare-entrantangle.
CHAPTERVIII
DRAWINGANDITSUTILITY
Aknowledgeofdrawing,atleastsofarasthefundamentalsareconcerned,isofgreatservicetothebeginner.Allwork,afterbeingconceivedinthebrain,shouldbetransferredtopaper.Ahabitofthiskindbecomesapleasure,and,ifcarriedoutpersistently,willproveasourceofprofit.Theboywithabowpencaneasilydrawcircles,andwithadrawingorrulingpenhecanmakestraightlines.
REPRESENTINGOBJECTS.--Butlethimtrytorepresentsomeobject,andthepensbecomeuseless.Thereisavastdifferenceintheuseofdrawingtoolsandfree-handdrawing.Whiletheboywhoisabletoexecute
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free-handsketchesmaybecomethebetterartist,stillthatartwouldnotbeofmuchservicetohimasacarpenter.First,becausetheuseoftoolsgivesprecision,andthisisnecessarytothebuilder;and,second,becausetheartistdealswhollywithperspectives,whereasthebuildermustexecutefromplanesurfacesorelevations.
FORMINGLINESANDSHADOWS.--Itisnotmyintentiontofurnishacompletetreatiseonthissubject,buttodotwothings,oneofwhichwillbetoshow,amongotherfeatures,howsimplelinesformobjects;howshadingbecomesaneffectiveaid;howproportionsareformed;and,second,howtomakeirregularforms,andhowtheymayreadilybeexecutedsothattheboymaybeabletograsptheideasforallshapesandstructuraldevices.
[Illustration:_Fig.125._]
[Illustration:_Fig.126._]
[Illustration:_Fig.127._]
ANALYSISOFLINESHADING.--InthedemonstrationofthisworkIshallgiveananalysisofthesimplelinesformed,showingthetermsusedtodesignatethelines,curves,andformations,sothatwhenanyworkislaidoutthebeginnerwillbeable,withthisglossarybeforehim,to
describearchitecturally,aswellasmathematically,theanglesandcurveswithwhichheisworking.
HOWTOCHARACTERIZESURFACE.--Supposewecommencesimplywithstraightlines.HowshallwedeterminethecharacterofthesurfaceofthematerialbetweenthetwostraightlinesshowninFig.125?Isitflat,rounded,orconcaved?Letusseehowwemaytreatthesurfacebysimplelinessoastoindicatetheconfiguration.
[Illustration:_Fig.128._]
[Illustration:_Fig.129._]
[Illustration:_Fig.130._]
[Illustration:_Fig.131._]
CONCAVESURFACES.--InFig.126theshadinglinescommenceattheuppermargin,andareheaviestthere,thelinesgraduallygrowingthinnerandfartherapart.
CONVEXSURFACES.--InFig.127theshadingisverylightalongtheuppermargin,andheavyatthelowermargin.Thefirstshadedfigure,therefore,representsaconcavedsurface,andthesecondfigureaconvexsurface.Butwhy?Simplyforthereasonthatindrawings,aswellasinnature,lightisprojecteddownwardly,hencewhenabeamoflight
movespastthemarginofanobject,thecontrastattheupperpart,wherethelightismostintense,isstrongest.
TheshadingoftheS-shapedsurface(Fig.128)isacompoundofFigs.126and127.
[Illustration:_Fig.132._]
SHADOWSFROMASOLIDBODY.--WecanunderstandthisbetterbyexaminingFig.129,whichshowsaverticalboard,andabeamoflight(A)passing
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downwardlybeyondtheuppermarginoftheboard.Undertheseconditionstheuppermarginoftheboardappearsdarkertothevision,bycontrast,thanthelowerpart.Itshouldalsobeunderstoodthat,ingeneral,thenearertheobjectthelighteritis,sothatastheupperedgeoftheboardisfarthestfromtheeyetheheavyshadingtherewillatleastgivetheappearanceofdistancetothatedge.
Butsupposethatinsteadofhavingthesurfaceoftheboardflat,itshouldbeconcaved,asinFig.130,itisobviousthatthehollow,ortheconcaved,portionoftheboardmustintensifytheshadowsorthedarknessattheupperedge.ThisexplainswhytheheavyshadinginFig.126isatthatuppermargin.
FLATEFFECTS.--Iftheboardisflatitmaybeshaded,asshowninFig.131,inwhichthelinesareallofthesamethickness,andarespacedfartherandfartherapartatregularlyincreasingintervals.
[Illustration:_Fig.133._]
[Illustration:_Fig.134._]
THEDIRECTIONOFLIGHT.--Now,indrawing,wemustobserveanotherthing.Notonlydoesthelightalwayscomefromabove,butitcomesalsofromtheleftside.IshowinFig.132twosquares,onewithintheother.All
thelinesareofthesamethickness.Canyoudeterminebymeansofsuchadrawingwhattheinnersquarerepresents?Isitablock,orraisedsurface,orisitadepression?
RAISEDSURFACES.--Fig.133showsitintheformofablock,simplybythickeningthelowerandtheright-handlines.
DEPRESSEDSURFACES.--If,bychance,youshouldmaketheupperandtheleft-handlinesheavy,asinFig.134,itwould,undoubtedly,appeardepressed,andwouldneednofurtherexplanation.
FULLSHADING,--But,inordertofurnishanadditionalexampleoftheeffectofshading,supposeweshadethesurfaceofthelargesquare,as
showninFig.135,andyouwillatonceseethatnotonlyistheeffectemphasized,butitallthemoreclearlyexpresseswhatyouwanttoshow.Inlikemanner,inFig.136,weshadeonlythespacewithintheinnersquare,anditisonlytooobvioushowshadowsgiveussurfaceconformation.
[Illustration:_Fig.135._]
[Illustration:_Fig.136._]
ILLUSTRATINGCUBESHADING.--InFig.137Ishowmerelyninelinesjoinedtogether,alllinesbeingofequalthickness.
Asthusdrawnitmayrepresent,forinstance,acube,oritmayshowsimplyasquarebase(A)withtwosides(B,B)ofequaldimensions.
SHADINGEFFECTS.--Now,toexamineitproperlysoastoobservewhatthedraughtsmanwishestoexpress,lookatFig.138,inwhichthethreediverginglines(A,B,C)areincreasedinthickness,andthecubeappearsplainly.Ontheotherhand,inFig.139,thethickeningofthelines(D,E,F)showsanentirelydifferentstructure.
[Illustration:_Fig.137._]
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[Illustration:_Fig.138._]
[Illustration:_Fig.139._]
Itmustberemembered,therefore,thattoshowraisedsurfacesthegeneraldirectionistoshadeheavilythelowerhorizontalandtherightverticallines.(SeeFig.133.)
HEAVYLINES.--Butthereisanexceptiontothisrule.Seetwoexamples(Fig.140).Heretwoparallellinesappearclosetogethertoformtheedgenearesttheeye.Insuchcasesthesecond,orupper,lineisheaviest.Onverticallines,asinFig.141,thesecondlinefromtherightisheaviest.Theseexamplesshowplaingeometricallines,andthosefromFigs.138to141,inclusive,areinperspective.
[Illustration:_Fig.140._]
[Illustration:_Fig.141._]
PERSPECTIVE.--Aperspectiveisamostdeceptivefigure,andacube,forinstance,maybedrawnsothatthevariouslineswilldifferinlength,andalsobeequidistantfromeachother.Orallthelinesmaybeofthesamelengthandhavethedistancesbetweenthemvary.Supposingwehave
twocubes,onelocatedabovetheother,separated,say,twofeetormorefromeachother.Itisobviousthatthelinesofthetwocubeswillnotbethesametoacamera,because,iftheywerephotographed,theywouldappearexactlyastheyare,sofarastheirpositionsareconcerned,andnotastheyappear.Butthecubesdoappeartotheeyeashavingsixequalsides.Thecamerashowsthattheydonothavesixequalsidessofarasmeasurementisconcerned.Youwillsee,therefore,thatthepositionoftheeye,relativetothecube,iswhatdeterminestheangle,or$therelative$anglesofallthelines.
[Illustration:_Fig.142._]
[Illustration:_Fig.143._]
ATRUEPERSPECTIVEOFACUBE.--Fig.142showsatrueperspective--thatis,itistruefromthemeasurementstandpoint.Itiswhatiscalledan_isometrical_view,orafigureinwhichallthelinesnotonlyareofequallength,buttheparallellinesareallspacedapartthesamedistancesfromeachother.
ISOMETRICCUBE.--Ienclosethiscubewithinacircle,asinFig.143.Toformthiscubethecircle(A)isdrawnandbisectedwithaverticalline(B).Thisformsthestartingpointforsteppingoffthesixpoints(C)inthecircle,usingthedividerswithoutresetting,afteryouhavemadethecircle.Thenconnecteachofthepoints(C)bystraightlines(D).Theselinesarecalledchords.Fromthecenterdrawtwolines(E)atan
angleandoneline(F)vertically.Thesearetheradiallines.Youwillseefromtheforegoingthatthechords(D)formtheoutlineofthecube--orthelinesfarthestfromtheeye,andtheradiallines(E,F)arethenearesttotheeye.Inthispositionwearelookingattheblockatatruediagonal--thatis,fromacorneratonesidetotheextremecornerontheoppositeside.
[Illustration:_Fig.144._]
Letuscontrastthis,andparticularlyFig.142,withthecubewhichis
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placedhigherup,viewedfromthesamestandpoint.
FLATTENEDPERSPECTIVE.--Fig.144showsthenewperspective,inwhichthethreeverticallines(A,A,A)areofequallength,andthesixangularlydisposedlines(B,C)areofequallength,butshorterthanthelinesA.TheonlychangewhichhasbeenmadeistoshortenthedistanceacrossthecornerfromDtoD,buttheverticallines(A)arethesameinlengthasthecorrespondinglinesinFig.143.Notwithstandingthischangethecubesinbothfiguresappeartobeofthesamesize,as,infact,theyreallyare.
[Illustration:_Fig.145._]
Informingaperspective,therefore,itwouldbeagoodideafortheboytohaveacubeofwoodalwaysathand,which,iflaiddownonahorizontalsupport,alongside,orwithinrangeoftheobjecttobedrawn,willserveasaguidetotheperspective.
TECHNICALDESIGNATIONS.--Asallgeometricallineshavedesignations,Ihaveincorporatedsuchfiguresaswillbemostserviceabletotheboy,eachfigurebeingaccompaniedbyitsproperdefinition.
[Illustration:_Fig.146._]
[Illustration:_Fig.147._]BeforepassingtothatsubjectIcanbettershowsomeofthesimpleformsbymeansofsuitablediagrams.
ReferringtoFig.145,letusdirectourattentiontothebody(G),formedbytheline(D)acrossthecircle.Thisbodyiscalledasegment.Achord(D)andacurvecompriseasegment.
SECTORANDSEGMENT.--Nowexaminetheshapeofthebodyformedbytwooftheradiallines(E,E)andthatpartofthecirclewhichextendsfromoneradiallinetotheother.Thebodythusformedisasector,anditismadebytworadiatinglinesandacurvedline.Learntodistinguish
readily,inyourmind,thedifferencebetweenthetwofigures.
TERMSOFANGLES.--Therelationofthelinestoeachother,themannerinwhichtheyarejoinedtogether,andtheircomparativeangles,allhavespecialtermsandmeanings.Thus,referringtotheisometriccube,inFig.145,theangleformedatthecenterbythelines(B,E)isdifferentfromtheangleformedatthemarginbythelines(E,F).TheangleformedbyB,Eiscalledanexteriorangle;andthatformedbyE,Fisaninteriorangle.Ifyouwilldrawaline(G)fromthecentertothecircleline,soitintersectsitatC,thelinesB,D,Gformanequilateralorisoscelestriangle;ifyoudrawachord(A)fromCtoC,thelinesH,E,Fwillformanobtusetriangle,andB,F,Haright-angledtriangle.
CIRCLESANDCURVES.--Circles,and,infact,allformsofcurvedwork,arethemostdifficultforbeginners.Thesimplestfigureisthecircle,which,ifitrepresentsaraisedsurface,isprovidedwithaheavylineonthelowerright-handside,asinFig.146;buttheproperartisticexpressionisshowninFig.147,inwhichthelowerright-handsideisshadedinringsrunningonlyapartofthewayaround,graduallydiminishinginlength,andspacedfartherandfartherapartasyouapproachthecenter,thusgivingtheappearanceofasphere.
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[Illustration:_Fig.148._]
IRREGULARCURVES.--Buttheirregularcurvesrequirethemostcaretoformproperly.Letustryfirsttheellipticalcurve(Fig.148).Theproperthingis,first,todrawaline(A),whichiscalledthe"majoraxis."Onthisaxiswemarkforourguidancetwopoints(B,B).Withthedividersfindapoint(C)exactlymidway,anddrawacrossline(D).Thisiscalledthe"minoraxis."Ifwechoosetodosowemayindicatetwopoints(E,E)ontheminoraxis,which,inthiscase,forconvenience,aresospacedthatthedistancealongthemajoraxis,betweenB,B,istwicethelengthacrosstheminoraxis(D),alongE,E.Nowfindone-quarterofthedistancefromBtoC,asatF,andwithacompasspencilmakeahalfcircle(G).If,now,youwillsetthecompasspointonthecentermark(C),andthepencilpointofthecompassonB,andmeasurealongtheminoraxis(D)onbothsidesofthemajoraxis,youwillmaketwopoints,asatH.Thesepointsareyourcentersforscribingthelongsidesoftheellipse.Beforeproceedingtostrikethecurvedlines(J),drawadiagonalline(K)fromHtoeachmarkingpoint(F).Dothisonbothsidesofthemajoraxis,andproducetheselinessotheycrossthecurvedlines(G).Whenyouinkinyourellipsedonotallowthecirclepentocrossthelines(K),andyouwillhaveamechanicalellipse.
ELLIPSESANDOVALS.--Itisnotnecessarytomeasurethecenteringpoints
(F)atcertainspecifieddistancesfromtheintersectionofthehorizontalandverticallines.Wemaytakeanypointalongthemajoraxis,asshown,forinstance,inFig.149.LetBbethispoint,takenatrandom.Thendescribethehalfcircle(C).Wemay,also,arbitrarily,takeanypoint,as,forinstance,DontheminoraxisE,andbydrawingthediagonallines(F)wefindmarksonthecircle(C),whicharethemeetinglinesforthelargecurve(H),withthesmallcurve(C).Inthiscasewehaveformedanovateoranovalform.Experiencewillsoonmakeperfectinfollowingoutthesedirections.
FOCALPOINTS.--Thefocalpointofacircleisitscenter,andiscalledthe_focus_.Butanellipsehastwofocalpoints,called_foci_,representedbyF,FinFig.148,andbyB,BinFig.149.
A_producedline_isonewhichextendsoutbeyondthemarkingpoint.ThusinFig.148thatpartofthelineKbetweenFandGrepresentstheproducedportionoflineK.
[Illustration:_Fig.149._]
SPIRALS.--Thereisnomoredifficultfiguretomakewithaboworacirclepenthanaspiral.InFig.150ahorizontalandaverticalline(A,B),respectively,aredrawn,andattheirintersectionasmallcircle(C)isformed.Thisnowprovidesforfourcenteringpointsforthecirclepen,onthetwolines(A,B).Intermediatethesepointsindicateasecondsetofmarkshalfwaybetweenthemarksonthelines.
Ifyouwillnowsetthepointofthecompassat,say,themark3,andthepencilpointofthecompassatD,andmakeacurvedmarkone-eighthofthewayaround,say,totheradialline(E),thenputthepointofthecompassto4,andextendthepencilpointofthecompasssoitcoincideswiththecurvedlinejustdrawn,andthenagainmakeanothercurve,one-