carpentry for boys by james slough zerbe

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.



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.


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.


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.


ANOILSTONEisasessentialasagrindstone.Forgivingagoodedgetotoolsitissuperiortoawaterstone.Itshouldbeprovidedwithatop,andcoveredwhennotinuse,tokeepoutdustandgrit.Thesearethe


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littlethingsthatcontributetosuccessandshouldbecarefullyobserved.

THEMITERBOX.--Thisshouldbe14incheslongand3"by3"inside,madeofhardwood3/4"thick.Thesidesshouldbenailedtothebottom,asshown.


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.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.


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.


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.


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.


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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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: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.


THEPLANE.--Thejackplaneandtheforeplanearehandledwithbothhands,andthesmoothingplanewithonehand,butonlywhenusedfordressingtheendsofboards.Forotherusesbothhandsarerequired.

ANGLESFORHOLDINGPLANES.--Beforecommencingtoplaneaboard,alwaysobservethedirectioninwhichthegrainofthewoodruns.Thisprecautionwillsavemanyapieceofmaterial,becauseifthejackplaneissetdeepitwillrunintothewoodandcausearoughsurface,whichcanbecuredonlybyanextraamountoflaborinplaningdown.

Nevermovethejackplaneorthesmoothingplaneovertheworksothatthebodyofthetoolisinadirectlinewiththemovementoftheplane.

Itshouldbeheldatanangleofabout12or15degrees(seeFig.25).Theforeplaneshouldalwaysbeheldstraightwiththemovementoftheplane,becausethelengthoftheforeplanebodyisusedasastraightenerforthesurfacetobefinished.


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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FRAMEWORK.--Aswenowknowthesizes,thefirstthingistobuildtheframework.Thelegsshouldbedressedsquareandsmootheddownwiththeforeplanetomakethemperfectlystraight.Now,layouttwomortisesattheupperendofeachleg.Followtheillustrationstoseehowthisisdone.

LAYINGOUTTHELEGS.--Fig.27showsalegwithsquarecrossmarks(A)ateachend.Thesemarksindicatethefinishedlengthoftheleg.Youwillalsoseecrossesontwosides.Theseindicatewhatiscalledthe"worksides."Theworksidesareselectedbecausetheyarethefinestsurfacesontheleg.



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.


THEMORTISES.--Whenthemortiseshavebeenmadetheywillappearas

shownintheenlargedcrosssectionoftheleg(Fig.30),thetotaldepthofeachmortisebeing1-1/2".Thedepthofthismortisedeterminesforusthelengthofthetenonsonthefacingboards.

THEFACINGBOARDS.--Theseboardsareeach1inchthickand7incheswide.Asthetopofthetableis42incheslong,andwemustprovideanoverhang,sayof2inches,wewillfirsttakeoff4inchesfortheoverhangand4inchesforthelegs,sothatthelengthoftwoofthefacingboards,fromshouldertoshoulder,mustbe34inches;andtheothertwofacingboards28inches.Then,aswemustadd1-1/2inchesforeachtenon,twooftheboardswillbe37incheslongandtwoofthem31incheslong.



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.



[Illusstration_Fig.35._]

TOOLSUSED.--Thebacksawisusedforcuttingthetenon,andtheendoftheboardappearsasshownintheenlargedFig.34.Twothingsarenownecessarytocompletethetenons.Ontheupperorworkedgeofeachboardusethegagetomarkoffahalf-inchslice,andthencutawaytheflatsideofthetenonattheend,onitsinnersurface,soitwillappearasshowninFig.35.


[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.


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.


THEDRAWER.--Thedrawer(Fig.41)shownincrosssection,hasitsfront(A)providedwithanoverlappingflange(B).

Itisnotourobjectinthischaptertoshowhoweachparticulararticleismade,butsimplytopointouttheunderlyingprinciples,andtoillustratehowthefasteningelements,thetenonsandmortises,areformed,sothattheboywillknowtheproperstepsintheirnaturalorder.


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.


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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PROPERTERMS.--Itistheapplicationofthecorrecttermstothingsthatlaysthefoundationforaccuratethinkingandproperexpressionsindescribingwork.Awisemanoncesaidthatthebasisoftruescienceconsistsincorrectdefinitions.

PICTUREFRAMES.--Inpictureframesthemiteredcornersmayhaveasawkerf(C)cutacrossthecorners,asshowninFig.44,andathinbladeofhardwooddrivenin,thewholebeinggluedtogether.

DOVETAILJOINTS.--Itisinthelayingoutofthemorecomplicateddovetailjointsthatthehighestskillisrequired,becauseexactnessisofmoreimportanceinthisworkthaninanyotherarticleinjoinery.Inordertodothisworkaccuratelyfollowouttheexamplesgiven,andyouwillsoonbeabletomakeabeautifuldovetailcorner,anddoitquickly.


PREPARINGABOXJOINT.--Inordertomatchaboxjointfortheinnerend

ofatabledrawer,thefirststepistoselecttwoworksides.Oneworksidewillbetheedgeoftheboard,andtheotherthesidesurfaceoftheboard,andonthosesurfaceswewillputcrosses,asheretoforesuggested.




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.




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.


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.


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.


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.


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.


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.




ANALYSISOFLINESHADING.--InthedemonstrationofthisworkIshallgiveananalysisofthesimplelinesformed,showingthetermsusedtodesignatethelines,curves,andformations,sothatwhenanyworkislaidoutthebeginnerwillbeable,withthisglossarybeforehim,to

describearchitecturally,aswellasmathematically,theanglesandcurveswithwhichheisworking.

HOWTOCHARACTERIZESURFACE.--Supposewecommencesimplywithstraightlines.HowshallwedeterminethecharacterofthesurfaceofthematerialbetweenthetwostraightlinesshowninFig.125?Isitflat,rounded,orconcaved?Letusseehowwemaytreatthesurfacebysimplelinessoastoindicatetheconfiguration.





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.


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.



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.



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.



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Itmustberemembered,therefore,thattoshowraisedsurfacesthegeneraldirectionistoshadeheavilythelowerhorizontalandtherightverticallines.(SeeFig.133.)

HEAVYLINES.--Butthereisanexceptiontothisrule.Seetwoexamples(Fig.140).Heretwoparallellinesappearclosetogethertoformtheedgenearesttheeye.Insuchcasesthesecond,orupper,lineisheaviest.Onverticallines,asinFig.141,thesecondlinefromtherightisheaviest.Theseexamplesshowplaingeometricallines,andthosefromFigs.138to141,inclusive,areinperspective.



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.



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.


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.


Informingaperspective,therefore,itwouldbeagoodideafortheboytohaveacubeofwoodalwaysathand,which,iflaiddownonahorizontalsupport,alongside,orwithinrangeoftheobjecttobedrawn,willserveasaguidetotheperspective.

TECHNICALDESIGNATIONS.--Asallgeometricallineshavedesignations,Ihaveincorporatedsuchfiguresaswillbemostserviceabletotheboy,eachfigurebeingaccompaniedbyitsproperdefinition.


[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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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.


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-

carpentry for boys by james slough zerbe

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