dimensioning guides

8/11/2019 Dimensioning Guides

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Dimensioning

Chapter 9


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5Technical Drawing 13thEditionGiesecke, Mitchell, Spencer, Hill Dygdon, Novak,

29 !earson "d#cation, $pper Saddle %iver, N&'()*+

-./ectives 6cont+7

$se aligned and #nidirectionaldimensioning systems

Dimension circles, arcs, andinclined s#r8aces

denti8y precision ranges 8or typical

man#8act#ring operations pply 3nish sym.ols and notes to

a draing


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(Technical Drawing 13thEditionGiesecke, Mitchell, Spencer, Hill Dygdon, Novak,


-./ectives 6cont+7

Dimension conto#rs $se standard practices 8or

dimensioning prisms, cylinders,holes, c#rves

List practices 8or dimensioning a

solid model as doc#mentation denti8y g#idelines 8or the do:s and

don:ts o8 dimensioning


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)Technical Drawing 13thEditionGiesecke, Mitchell, Spencer, Hill Dygdon, Novak,


$nderstanding

Dimensioning Draings 8or prod#cts m#st .e

dimensioned so that prod#ction

personnel all over the orld canmake mating parts that ill 3tproperly hen assem.led or hen

#sed to replace parts


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;Technical Drawing 13thEditionGiesecke, Mitchell, Spencer, Hill Dygdon, Novak,


spects o8 Good

Dimensioning Dimensions are given in the 8orm o8

distances, angles, and notes

regardless o8 the dimensioning #nits.eing #sed


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hen a 3nished part is meas#redit may vary slightly 8rom the e4act

dimension speci3ed


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Lines $sed in

Dimensioning Dimension line ? a thin, dark, solid

line terminated .y arroheads,

indicating the direction and e4tento8 a dimension


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Lines $sed in

Dimensioning "4tension line ? a thin, dark, solid

line that e4tends 8rom a point on

the draing to hich a dimensionre8ers


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Lines $sed in

Dimensioning Centerline ? a

thin, dark linealternating longand short dashescommonly #sedin locating holesand othersymmetrical8eat#res


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$sing Dimension and

"4tension Lines Shorter dimension lines are nearest

the o./ect o#tline

Dimension lines sho#ld not crosse4tension lines dimension line sho#ld never

coincide ith or e4tend any line o8

the draing void crossing dimension lines hen

possi.le


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$sing Dimension and

"4tension Lines


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$sing Dimension and

"4tension Lines Dimensions sho#ld .e lined #p and

gro#ped together as m#ch as

possi.le


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Leaders

leader is a thin solid linedirecting attention to a note or

dimension and starting ith anarrohead or dot


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Technical Drawing 13thEditionGiesecke, Mitchell, Spencer, Hill Dygdon, Novak,


Draing Scale and

Dimensioning Draings are #s#ally made to a scale

hich is indicated in the title .lock

heavy straight line sho#ld .edran #nder any single dimensionval#e that is not to scale 8 an entire draing is not prepared to a

standard, note N-N" in the scale area o8the title .lock


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Direction o8 Dimension

Aal#es and Notes ll dimension val#es and notes are

lettered hori1ontally and sho#ld

read 8rom the .ottom o8 the sheet


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Direction o8 Dimension

Aal#es and Notes


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Dimension $nits

Dimension val#es are shon #sing themetric system or decimal inch val#es

t is standard practice to omitmillimeter designations and inchmarks on draings and note the #nitsin the title .lock e4cept hen there is

a possi.ility o8 mis#nderstanding


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Dimension $nits

"ither meters or 8eet and inchesand 8ractional inches are #sed in

architect#ral and str#ct#ral ork n $+S+ str#ct#ral and architect#ral

dra8ting, all dimensions o8 @ 8oot orover are #s#ally e4pressed in 8eet andinches


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Millimeter Aal#es


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Decimal nch Aal#es


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%#les 8or Dimension

Aal#es >here the metric dimension is a

hole n#m.er, do not sho adecimal point or a 1ero

>here the metric dimension is lessthan @mm, a 1ero precedes thedecimal point

>here the decimalBinch dimension is#sed, a 1ero is not #sed .e8ore thedecimal point o8 val#es less than @


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2)Technical Drawing 13thEditionGiesecke, Mitchell, Spencer, Hill Dygdon, Novak,


%o#nding Aal#es

8 the n#m.er 8olloing the ro#ndingposition is a ), ro#nd to an even

n#m.er 8 the n#m.er 8olloing the ro#nding

position is less then ), make no

change 8 the n#m.er 8olloing the ro#nding

position is more than ), ro#nd #p


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D#al Dimensioning

D#al dimensioning is #sed to shometric and decimal inch

dimensions on the same draing


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Dimension Sym.ols


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!lacing Dimensions

Never letter a dimension val#e overany line on the draing

n a gro#p o8 parallel dimensionlines, the dimension val#es sho#ld.e staggered

Do not crod dimension 3g#res intolimited spaces making themillegi.le


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!lacing Dimensions

!lace dimensions .eteen vieshen possi.le, .#t only attached

to a single vie Dimensions sho#ld not .e placed

on a vie #nless doing so

promotes the clarity o8 the draing


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!lacing Dimensions

>hen a dimension m#st .e placedin a hatched area or on the vie,

leave an opening in the hatchingor a .reak in the lines 8or thedimension val#e


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!lacing Dimensions

void dimensioning to hidden lines Do not attach dimensions to visi.le

lines here the meaning is not clear Notes 8or holes are #s#ally placed

here yo# see the circ#lar shape o8the hole n e4ternal cylindrical shape is

dimensioned here it appearsrectang#lar


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!lacing Dimensions

Give dimensions here theconto#rs o8 the o./ect are de3ned


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S#per#o#s Dimensions

ll necessary dimensions m#st .eshon .#t avoid giving

#nnecessary dimensions Do not repeat dimensions on the

same vie or on dierent vies, or

give the same in8ormation todierent ays


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S#per#o#s Dimensions


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Dimensioning ngles

Eo# sho#ld dimension angles .yspeci8ying the angle in degrees

and a linear dimension


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5;Technical Drawing 13thEditionGiesecke, Mitchell, Spencer, Hill Dygdon, Novak,


Dimensioning rcs

circ#lar arc is dimensioned in thevie here yo# see its tr#e shape

.y giving the val#e 8or its radi#spreceded .y the a..reviation %


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5'Technical Drawing 13thEditionGiesecke, Mitchell, Spencer, Hill Dygdon, Novak,


Fillets and %o#nds

ndivid#al 3llets and ro#nds aredimensioned like other arcs

8 there are only a 8e and they areo.vio#sly the same si1e, giving onetypical radi#s is pre8erred

Fillets radii can also .e given in ageneral note


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Si1e Dimensions= !risms


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Si1e Dimensions= Cylinders


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Si1e Dimensions= Holes


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Dimensioning Aario#s

Shapes


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Dimensioning C#rves


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Dimensioning C#rved

S#r8aces


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Dimensioning %o#ndedBend

Shapes


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Dimensioning


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Dimensioning


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Dimensioning Cham8ers


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Dimensioning eyays


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Dimensioning n#rls


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S#r8ace %o#ghness


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Location Dimensions


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Location Dimensions


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Location Dimensions


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Location Dimensions


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Mating Dimensions


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Coordinate Dimensioning

asic coordinate dimensioningpractices are generally compati.le

ith the data re0#irements 8ora#tomated prod#ction

set o8 three m#t#ally

perpendic#lar dat#m or re8erenceplanes is #s#ally re0#ired 8orcoordinate dimensioning


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Machine, !attern, and Forging

Dimensions


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SheetBMetal ends

n sheetBmetal dimensioning,alloance m#st .e made 8or .ends


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Notes

t is #s#ally necessary tos#pplement the direct dimensions

ith notes Notes sho#ld .e orded to allo

only one interpretation

Notes sho#ld .e letteredhori1ontally


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Standards

Dimensions sho#ld .e given tomake #se o8 readily availa.le

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