Engineering Drawing Guide

166 Pages·2002·4.3 MB·Urdu

by  Md.Samiullah Bakhtari

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CONTENTS
(1) DrawingInstrumentsandMaterials-------- i to 4
(2) LinesandLettering------------------------ s to 14 ------------------------------- L/yr
(3) Singsand Symbols------------------------ 15 to is-----------
(4) BasicConstructions------------------------16 to 19
(5) GeometricalConstructions--------------- 20 to 38
(6) ConicSections------------------------------39 to 54
(7) Scales----------------------------------------55 to s?
(8) ProjectionsofPoints- -------------------88 to 102
(9) ProjectionsofSolids--------------........103 to n6
(10) IsometricProjections------------- ------117 12.5
(11) BuildingDrawing----------------------...126to 136
(12) Stairs-------------------------------------- 137 to 142
(13) BrickandBrickworks------------------ us to 150
(14) SepticTank- ---------------------------- isito 151-
(15) Trusses------------------------------------152 to 159 ----------------------------------------ij^'j

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Drawing Instrument Material
Engineering Drawing is the language ofengineers. The
accuracyandneatnessofengineeringdrawingdependsonthe
quality ofthe instruments used. The drawing can be well
preparedwithgoodinstruments.Acomprehensiveknowledge
ofthe drawing instruments, material and drawing practices
will enable studentsto prepare accurate and neatdrawings.
Thedifferentdrawinginstrumentsandmaterials,methodsof
usingthemareexplainedbelow.
The following list of instruments and other drawing
materialisrequiredforthestudents.
(1) DrawingBoardwhichshouldbefixedonthestand.
(2) MiniDrafter(withouterror)
(3) Protractor
(4) InstrumentBox
(5) FrenchCurves
(6) DrawingPaper
((/78ox)) DPernacwii.l.nSg,,haPernpcnielrs(HB, 1H,2H,etc) (Battens)0>r* -<!:c-(f}>?6(+jttoirfv\j&^*.
(9) SandPaper(forsharpeningthepencils)
(10) DrawingBoardClamps
(11) PencilEraser(Rubber)etc.
striApsDorfawweilnlgseBaosaorndedissorfetctwaonogdul,aranidntshheaptewoanbdatitsemnsadfeixeodf ^, ^^^^*'?-^^. ~^(/^ot+ bQquareMsj*l/1*d^ic* ^
atthebackoftheDrawingBoard.
TheDrawingBoardshouldbefixed onthemetallicstand
or kept any other table, with its working surface sloping
downwardstowardsthestudentforconvenience.
NowadaysSet-Squaresaremadeoftransparentmaterials,
the lines underneath can beeasily seen. The Set-Square are
triangular in shapeandoneoftheangles isarightangle. ^J?OJ(/^^jfbx(Semi Circular
Semi Circular Protractors are generally made of
transparentplasticmaterial,theworkingedgeofProtractor
isusuallybevelled.
TheSemi-CircularProtractorisabout 100mmindiameter
andisgraduatedatevery 1 intervalreadablefromboththe
ends. The straight line that is markedjoining & 180 is
calledthe base ofthe Protractor. The Centre ofthe.base is
markedbyalineperpendiculartoit.
The Compass isthe mostfrequentlyused element inthe
instrumentbox.Itisusedfordrawingcircleswithpencil. It
consistsoftwolegshangedtogetheratthetopend(figIM3).
Anadjustablepointedneedleisfittedatthelowerendofone
leg.Apencilleadisinsertedatthelowerendoftheotherleg
whichisprovidedwithakneejoint.
For drawing circles of small diameter and arcs of
comparatively smallerradii,SmallBowCompass(figIM6) \,iJ^bwJUs(Frenchcurves)^!)
isused.
Divider also consists oftwo legs hinged together at the
top end. A steel point is provided at the lower end ofeach
leg. (figlM?) fx>
French Curves are also made oftransparent material.
Theseareusedtodrawcurvedlines.
Drawing Pencils is the most important tool used in
engineeringdrawing. DrawingPencils aremade in different
grades. The "HB" grade pencil is medium soft and dark in
blackcolour,whereas 1H,2H,gradepencilshardandlightin
blackcolour. "HB" Pencil isused forfreehandworks. Thin
and lightlinesdrawnby 1H&2Hpencils.
Drawing Pins are used to fix the drawing sheet oh the
drawing board at the required place. Frequent use ofpins ^. <,*jjrt /
spoiledthesurfaceoftheboard.ltisbettertouseboardclamps
insteadofpins.
Eraser(Rubber)isusedtoremovetheextralinesandline
drawn bymistakes. The eraserused shouldbe suchthatthe *>
surfaceofthedrawingpaperisnotspoiledinanyway.Useof &
erasershouldbeminimizebyproperplanning.
_;FiguresforDrawingInstrument&Materialwillbeshown
* inthenextpages.
Drawingboard
Parallel bar \
arms Protractor
^-Drawingsheet
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