GD&T Book#2
September 3, 2022 | Author: Anonymous | Category: N/A
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Date of Publication: January 12, 1! "atest #evision Date: $ay 1, 1
GM
General Motors Truck Group
DIMENSINA! ENGINEE"ING %ased on the &'$( )1*.+$ 1* Dimensioning and -olerancing 'tandard as amended by the GM Global Addendum-1997
GM
General Motors Truck Group
opyright c 1! by /eneral $otors orp. &"" #0/-' #0/-' #('(# #('(#(D (D
No part of this publication may be reproduced, stored in a retrieval system, or transmitted in any form or by any means, electronic, mechanical, recording or otherwise without prior written permission of the author and publisher.
Tolerances o# $orm Stra%&htness 3&'$( )1*.+$1*, 4.*.15
$latness 3&'$( )1*.+$1*, 4.*.25
'%rcular%ty 3&'$( )1*.+$1*, 4.*.65
'yl%ndr%c%ty 3&'$( )1*.+$1*, 4.*.*5
E(treme )ar%at%ons o# $orm E(treme Allo*ed +y S%,e Tolerance 2+.1 2+
2+ 3$$5
2+.1 3"$5
2+.1 3"$5
$$ Perfect 7orm %oundary 3$$5 2+
2+.1 3"$5
Internal $eature o# S%,e
E(treme )ar%at%ons o# $orm E(treme Allo*ed +y S%,e Tolerance 2+ 2*.
2*. 3"$5
2+ 3$$5
2*. 3"$5
$$ Perfect 7orm %oundary
2+ 3$$5
2*. 3"$5
E(ternal $eature o# S%,e
Stra%&htness $lat Sur#aces. .+
.1
2+ 89.2+
.1 -olerance lerance
.+ -olerance lerance
'traightness is the condition where an element of a surface or an a;is is a straight line
Stra%&htness $lat Sur#aces. .+ -olerance =one
2+.2+ ma; 2*.e tolerance
'yl%ndr%c%ty .1
.1 -olerance =one
$$
In this example the entire surface must lie within a tolerance zone defined by two concentric c oncentric cylinders separated by the specified tolerance value. All All points on the surface must lie within the limits of size and the cylindricity limit.
ylindricity is the condition of a surface of revolution in which all points are e?uidistant from a common a;is. ylindricity is a composite control of form which includes circularity 3roundness5, straightness, and taper of a cylindrical feature.
$orm 'ontrol u%, Cuestions A1+ 7ill in blans 3choose from below5
1. -he four form controls are _______ ____________ _____ , _______ ________ _ , ___________ ________ ___ , and ______ ____________ ______ . 2. #ule A1 states that unless otherwise specified a feature of si>e must have ________ ____________ ____ at at $$. 6. ________ ____________ ____ and ________ ___________ ___ are individual line or circular element 32D5 controls. and ______ are surface 36D5 controls. ____________ ______ are *. ________ and and _______ cylindrical cylindrical +. ircularity can be applied to both ________ and parts.
stra%&htness stra%&ht per#ect #orm
cyl%ndr%c%ty an&ular%ty tapered #latness pro#%le c%rcular%ty true pos%t%on
&nswer ?uestions ?uestions A41 A41 -rue -rue o orr 7alse
4. 7orm controls re?uire a datum reference. e. t han itBs si>e !. & featureBs form tolerance must be less than tolerance.
. 7latness controls the orientation of a feature. 1. 'i>e limits implicitly control a featureBs form.
Tolerances o# r%entat%on An&ular%ty 3&'$( )1*.+$1* ,4.4.25
2erpend%cular%ty 3&'$( )1*.+$1* ,4.4.*5
2arallel%sm 3&'$( )1*.+$1* ,4.4.65
An&ular%ty
37eature 'urface to Datum 'urface5 2 89.+ .6 & 6 o
A 1.+ min
2.+ ma;
6 o
A
.6 @ide -olerance =one
6 o
A
.6 @ide -olerance =one
The tolerance zone in this example is defined by to parallel planes oriented at the specified angle to the datum reference plane!
&ngularity is the condition &ngularity condition of the planar planar feature su surface rface at a specified angle 3other than degrees5 to the datum reference plane, within the specified tolerance >one.
An&ular%ty
37eature &;is to Datum 'urface5 $%T&' Tolerance applies to feature at (FS .6 &
.6 ircular -olerance leran ce =one =o ne
.6 ircular -olerance =one =on e
4 o
A
The tolerance zone in this example is defined by a cylinder e"ual to the length of the feature# oriented at the specified angle to the datum reference plane!
A
&ngularity is the con condition dition of tthe he feature a;is a;is at a specified specified angle 3other than degrees5 to the datum reference plane, within the specified tolerance >one.
An&ular%ty
37eature &;is to Datum Datum &;is5 &;is5 $%T&' Feature axis must lie ithin tolerance zone cylinder
. 6 &
$%T&' Tolerance applies to feature at (FS
A
.6 ircular -olerance leranc e =one =on e
.6 ircular -olerance =one =o ne *+ o
Datum &;is & The tolerance zone in this example is defined by a cylinder e"ual to the length of the feature# oriented at the specified angle to the datum reference axis!
&ngularity is the con condition dition of tthe he feature a;is a;is at a specified specified angle 3other than degrees5 to the datum reference a;is, within the specified tolerance >one.
2erpend%cular%ty 37eature 'urface to Datum 'urface5 .6 &
A .6 @ide -olerance =one
A
.6 @ide -olerance =one
The tolerance zone in this example is defined by to parallel planes oriented perpendicular perpendic ular to the datum ref reference erence plane!
A
Perpendicularity is the condition of the planar feature surface at a right angle to the datum reference plane, within the specified tolerance >one.
2erpend%cular%ty 37eature &;is to Datum 'urface5 .6 Diameter -olerance leranc e =one =o ne
$%T&' Tolerance applies to
.6 ircular -olerance =one
'
feature at (FS
.6 ircular -olerance =one =on e .6
The tolerance zone in this example is defined by a cylinder e"ual to the length of the feature# oriented perpendicular to the datum reference plane!
Perpendicularity is the condition of the feature a;is at a right angle to the datum reference plane, within the specified tolerance >one.
2erpend%cular%ty 37eature &;is to Datum Datum &;is5 &;is5 $%T&' Tolerance applies to feature at (FS .6 &
A
.6 @ide -olerance =one
Datum &;is & The tolerance zone in this example is defined by to parallel planes oriented perpendicular perpendic ular to the datum re reference ference ax axis! is!
Perpendicularity is the condition of the feature a;is at a right angle to the datum reference a;is, within the specified tolerance >one.
2arallel%sm
37eature 'urface to Datum 'urface5
.6 &
2+ 89.+
A .6 @ide -olerance =one
2+.+ ma;
.6 @ide -olerance =one
2*.+ min
A
The tolerance zone in this example is defined by to parallel planes oriented parallel to the datum reference plane!
A
Parallelism is the condition of the planar feature surface e?uidistant at all points from the datum reference plane, within the specified tolerance >one.
2arallel%sm
37eature &;is to Datum 'urface5 $%T&' The specified tolerance does not apply to the orientation of the feature axis in this direction
$%T&' Tolerance applies to feature at (FS
.6 @ide -olerance =one
.6 &
A
The tolerance zone in this example is defined by to parallel planes oriented parallel to the datum reference plane!
A
Parallelism is the condition of the feature a;is e?uidistant along its length from the datum reference plane, within the specified tolerance >one.
2arallel%sm
37eature &;is to Datum 'urfaces5 .6 ircular -olerance =one =o ne
+
$%T&' Tolerance applies to feature at (FS .6 ircular -olerance =one =o ne
.6 ircular -olerance leran ce =one =o ne .6 & %
+
A
The tolerance zone in this example is defined by a cylinder e"ual to the length of the feature# oriented parallel to the datum reference planes!
A
Parallelism is the condition of the feature a;is e?uidistant along its length from the two datum reference planes, within the specified tolerance >one.
2arallel%sm
37eature &;is to Datum Datum &;is5 &;is5 The tolerance zone in this example is defined by a cylinder e"ual to the length of the reference feature# oriented to the datum axis! parallel $%T&' Tolerance applies to feature at (FS .1 ircular -olerance leran ce =one =o ne
& .1 & .1
A
.1 ircular -olerance =one
Datum &;is &
Parallelism is the condition of the feature a;is e?uidistant along its length from the datum reference a;is, within the specified tolerance >one.
r%entat%on 'ontrol u%, Cuestions A1+ 7ill in blans 3choose from below5
1. -he three orientation controls are ________ __________ __ , ________ ___________ ___ , and ________ ________________ ________ . 2. & _______ _______________ ________ is always re?uired when applying any of the orientation controls.
6. ________ ________________ ________ is the appropriate geometric tolerance when controlling the orientation of a feature at right angles to a datum reference.
_________ _ . *. $athematically all three orientation tolerances are ________ of a feature. +. Erientation tolerances do not control the ________ of
perpend%cular%ty datum #eature an&ular%ty
datum tar&et locat%on %dent%cal
datum re#erence parallel%sm pro#%le
&nswer ?uestions ?uestions A41 A41 -rue -rue o orr 7alse
4. Erientation tolerances indirectly control a featureBs form. ones can be cylindrical. !. -o apply a perpendicularity tolerance the desired angle must be indicated as a basic dimension.
. Parallelism tolerances do not apply to features of si>e. desired ired angle must 1. -o apply an angularity tolerance the des be indicated as a basic dimension.
Tolerances o# "unout '%rcular "unout 3&'$( )1*.+$1*, 4.e F 7 F $a;. 7astener 'i>e F
- F 1.2+ 1 - F MMMMMM
& Calculate $ominal Size
2;
LL.LL .+
89 .2+
$
remember' the size tolerance must be added to the calculated MMC MMC hole size to obtain the correct nominal /alue!
? > $ 8T 7 F $a;. 7astener 'i>e F - F Posit Positional ional -olerance F
%
1.2+ 1
F 1 8 .+ F MMMMMM
1 .+
7loating 7asteners 0n applications where two or more mating details are assembled, and all parts have clearance holes for the fasteners, the floating fastener formula shown formula shown below can be used to calculate the appropriate hole si>es or positional tolerance re?uirements to ensure assembly. -he formula will provide a G>erointerferenceH fit when the features are at $$ and at their e;treme of positional tolerance
2; $1 I 1.+ 3#eference5
0eneral "uation Applies to "ach 1art Individually
F78- or -F7
&
?> M%n0 d%ameter o# clearance hole $> Ma(%mum d%ameter o# #astener T> 2os%t%onal tolerance d%ameter
%
2;
1.+ 89 .2+ .2+ $
Calculate (e"uired 5ositional Tolerance
T>?-$ F $inimum ole 'i>e F 7 F $a;. 7astener 'i>e F
- F 1.2+ 1 - F .2+
& 2;
Calculate $ominal Size
1.e F - F Posit Positional ional -olerance F
%
1.2+ 1
F F
1 8 .+ 1.+ $inimum
1 .+
(&M&M;&(erointerferenceH fit when the features are at $$ and at their e;treme of positional tolerance. 3Note that in this e;ample the positional tolerances indicated are the same for both parts.5
&PP"0(' @(N & P#EJ(-(D -E"(#&N( E"(#&N( = =EN( EN( 0' '(D 2; $1 I 1.+ 3#eference5
>eneral &"uation 3sed ?hen 5ositional Tolerances )re &"ual
F782- or -F37592
&
1
?> M%n0 d%ameter o# clearance hole $> Ma(%mum d%ameter o# #astener T> 2os%t%onal tolerance d%ameter
%
Calculate (e"uired Clearance ole Size!
2;
LL.LL 89 .2+ .!
$
&
.!
$ P
? > $ 8 @T $ominal Size -MMC For Calculations.
2I $1 I 1.+ 1
remember' the size tolerance must be added to the calculated MMC MM C size to obtain the correct nominal /alue!
7 F $a;. 7astener 'i>e F - F Posit Positional ional -olerance F
F 1. 8 23.!5 F MMMMM %
1. .!
7i;ed 7asteners 0n fixed fastener applications applications where two mating details have e?ual positional tolerances, the fixed fastener formula shown formula shown below can be used to calculate the appropriate minimum clearance hole si>e and9or positional tolerance re?uired to ensure assembly. -he formula provides a G>erointerferenceH fit when the features are at $$ and at their e;treme of positional tolerance. 3Note that in this e;ample the positional tolerances indicated are the same for both parts.5
&PP"0(' @(N & P#EJ(-(D -E"(#&N( E"(#&N( = =EN( EN( 0' '(D 2; $1 I 1.+ 3#eference5
>eneral &"uation 3sed ?hen 5ositional Tolerances )re &"ual
F782- or -F37592
&
1
?> M%n0 d%ameter o# clearance hole $> Ma(%mum d%ameter o# #astener T> 2os%t%onal tolerance d%ameter
%
Calculate (e"uired Clearance ole Size!
2;
11.!+ .!
89 .2+
$
&
.!
$ P
? > $ 8 @T $ominal Size -MMC For Calculations.
2I $1 I 1.+ 1
remember' the size tolerance must be added to the calculated MMC MM C size to obtain the correct nominal /alue!
7 F $a;. 7astener 'i>e F - F Posit Positional ional -olerance F
1. .!
F 1. 8 23.!5 F 11.4 11.4 $inimum %
(&M&M;&(erointerferenceH fit when the features are at $$ and at their e;treme of positional tolerance. 3Note that in this e;ample the positional tolerances indicated are the same for both parts.5
&PP"0(' @(N & P#EJ(-(D -E"(#&N( E"(#&N( = =EN( EN( 0' '(D 2; $1 I 1.+ 3#eference5
>eneral &"uation 3sed ?hen 5ositional Tolerances )re &"ual
F782- or -F37592
&
1
?> M%n0 d%ameter o# clearance hole $> Ma(%mum d%ameter o# #astener T> 2os%t%onal tolerance d%ameter
%
Calculate (e"uired Clearance ole Size!
2;
11.!+ .!
89 .2+
$
&
.!
$ P
? > $ 8 @T $ominal Size -MMC For Calculations.
2I $1 I 1.+ 1
remember' the size tolerance must be added to the calculated MMC MM C size to obtain the correct nominal /alue!
7 F $a;. 7astener 'i>e F - F Posit Positional ional -olerance F
F 1 8 23.!5 F 11.4 11.4 $inimum %
1 .!
(&M&M;&(erointerferenceH fit when the features are at $$ and at their e;treme of positional tolerance. 3Note: in this e;ample the resultant positional tolerance is applied to both parts e?ually.5
&PP"0(' @(N & P#EJ(-(D -E"(#&N( E"(#&N( = =EN( EN( 0' '(D 2; $1 I 1.+ 3#eference5
>eneral &"uation 3sed ?hen 5ositional Tolerances )re &"ual 1
F782- or -F37592
&
?> M%n0 d%ameter o# clearance hole $> Ma(%mum d%ameter o# #astener T> 2os%t%onal tolerance d%ameter
%
2;
11.2+ 89 .2+ .+ $
&
T > ? - $.3@ F $inimum ole 'i>e F 7 F $a;. 7astener 'i>e F
2I $1 I 1.+
$ominal Size -MMC For Calculations.
.+
%
Calculate (e"uired 5ositional Tolerance ! -;oth 5arts.
$ P
1
- F 311 1592 - F .+
11 1
(&M&M;&(erointerferenceH fit when the features are at $$ and at their e;treme of positional tolerance. 3Note that in this e;ample the positional tolerances indicated are not e?ual.5
&PP"0(' @(N & P#EJ(-(D -E"(#&N( E"(#&N( = =EN( EN( 0' '(D 2; $1 I 1.+
>eneral &"uation 3sed ?hen 5ositional Tolerances )re $ot &"ual
3#eference5
1
F783-1 8 -25
&
? > M%n0 d%ameter o# clearance hole $ > Ma(%mum d%ameter o# #astener T1> 2os%t%onal tolerance 2art A. T@> 2os%t%onal tolerance 2art +.
%
Calculate (e"uired Clearance ole Size!
2;
LL.LL 89 .2+ .+ $
& 2I $1 I 1.+ 1 $ P 1
$ominal Size -MMC For Calculations.
remember' the size tolerance must be added to the calculated MMC MMC hole size to obtain the correct nominal /alue!
F783-1 8 -25 7 F $a;. 7astener 'i>e F -1 F Positional -ol. 3&5 F -2 F Positional Posit ional -ol. 3%5 F
F 18 3.+ 8 15 F MMMM %
1 .+ 1
7i;ed 7asteners 0n fixed fastener applications where two mating details have une?ual positional tolerances, the fixed fastener formula shown formula shown below can be used to calculate the appropriate minimum clearance hole si>e and9or positional tolerances re?uired to ensure assembly. -he formula provides a G>erointerferenceH fit when the features are at $$ and at their e;treme of positional tolerance. 3Note that in this e;ample the positional tolerances indicated are not e?ual.5
&PP"0(' @(N & P#EJ(-(D -E"(#&N( E"(#&N( = =EN( EN( 0' '(D 2; $1 I 1.+
>eneral &"uation 3sed ?hen 5ositional Tolerances )re $ot &"ual
3#eference5
1
F 783-1 8 -25
&
? > M%n0 d%ameter o# clearance hole $ > Ma(%mum d%ameter o# #astener T1> 2os%t%onal tolerance 2art A. T@> 2os%t%onal tolerance 2art +.
%
Calculate (e"uired Clearance ole Size!
2;
11.e F -1 F Positional Posit ional -ol. 3&5 F -2 F Positional Posit ional -ol. 3%5 F
F 1 8 3.+ 8 15 F 11.+ 11.+ $inimum %
1 .+ 1
(&M&M;&(e re?uired to ensure assembly. -he formula provides a G>erointerferenceH fit when the features are at $$ and at the e;treme positional tolerance.
&PP"0(' @(N & P#EJ(-(D -E"(#&N( E"(#&N( =EN( =EN( 0' NE- '(D
7
P
F $in. diameter of clearance hole 7F $a;imum diameter of pin
&
-1F Positional tolerance 3Part &5 -2F Positional tolerance 3Part %5 DF $in. depth of pin 3Part &5 PF $a;imum proection of pin
%
D
Calculate $ominal Size
2;
LL.LL 89.2+ .+ $
& 2;
remember' the size tolerance must be added to the calculated MMC MMC hole size to obtain the correct nominal /alue!
F 7 8 -1 8 -2 31832P9D55
1.+ 89.+ .+ $
7 F $a;. pin si>e -1 F Positional Posit ional -ol. 3&5 -2 F Positional Posit ional -ol. 3%5 F $in. pin depth F $a;. pin proection
F
1 F .+ F .+ D F 2. P F 1+
%
F 1. 8 .+ 8 .+31 8 231+9255 F MMMMMMMMMM
7i;ed 7asteners 0n applications where a pro@ected a pro@ected tolerance zone zone is not indicated, it is necessary to select a positional tolerance and minimum clearance hole si>e combination that will allow for any outofs?uareness of the feature containing the fastener. fast ener. -he -he modified fixed fastener formula shown formula shown below can be used to calculate the appropriate minimum clearance hole si>e re?uired to ensure assembly. -he formula provides a G>erointerferenceH fit when the features are at $$ and at the e;treme positional tolerance.
&PP"0(' @(N & P#EJ(-(D -E"(#&N( E"(#&N( =EN( =EN( 0' NE- '(D
7
P
F $in. diameter of clearance hole 7F $a;imum diameter of pin
&
-1F Positional tolerance 3Part &5 -2F Positional tolerance 3Part %5 DF $in. depth of pin 3Part &5 PF $a;imum proection of pin
%
D
Calculate $ominal Size
2;
12 89.2+ .+ $
& 2;
F 7 8 -1 8 -2 31832P9D55
remember' the size tolerance must be added to the calculated MMC MMC hole size to obtain the correct nominal /alue!
F 7 8 -1 8 -2 31832P9D55
1.+ 89.+ .+ $
7 F $a;. pin si>e -1 F Positional tol. 3&5 -2 F Positional tol. 3%5 F $in. pin depth F $a;. pin proection
F 1 F .+ F .+ D F 2 P F 1+
%
F 1 8 .+ 8 .+31 8 231+9255 F 11.e of a feature. or unilateral . 6. Profile tolerances can be applied bilateral or
line tolerances are 2dimensional controls. *. 5rofile of a line surface tolerances are 6dimensional controls. +. 5rofile of a surface Composite e 5rofile 5rofile can be used when different tolerances are 4. Composit re?uired for location and form and9or orientation.
e of 7eature
&;is "ocation of $$ ole 'hown at (;treme "imit
1
&pplicable &pplicabl e /eometri /eometric c -olerance
12.+
irtual ondition %oundary
"esultant 'ond%t%on +oundary 0nternal 7eature 3$$ oncept5 1* 89 .+ 1$ & %
&
II.I
%
II.I
&s 'hown on Drawing
3
#esultant ondition Euter %oundary $inimum ircumscribed Diameter
2 Positional -olerance =one at "$
5
-rue 3%asic5 Position of ole Ether Possible (;treme "ocations %oundary of "$ ole 'hown at (;treme "imit
-rue 3%asic5 Position of ole
'alculat%n& "esultant 'ond%t%on 30nternal 7eature5 1*.+
"$ 'i>e of 7eature
&;is "ocation of "$ ole 'hown at (;treme "imit
2
/eomet /eometric ric -olerance 3at "$5
14.+
#esultant ondition %oundary
irtual i rtual ondition %oundary %oundary (;ternal 7eature 3$$ oncept5 1* 89 .+ 1$ & %
&
II.II
%
II.I
&s 'hown on Drawing
3
irtual ondition Euter %oundary $inimum ircumscribed Diameter
1 Positional -olerance =one at $$
5
-rue 3%asic5 Position of 7eature Ether Possible (;treme "ocations %oundary of $$ 7eature 'hown at (;treme "imit
-rue 3%asic5 Position of 7eature
alculating irtual ondition 1*.+
$$ 'i>e of 7eature
&;is "ocation of $$ 7eature 'hown at (;treme "imit
1 1+.+
&pplicable &pplicabl e /eometri /eometric c -olerance irtual ondition %oundary
"esultant 'ond%t%on +oundary (;ternal 7eature 3$$ oncept5 1* 89 .+ 1$ & %
&
II.I
%
II.I
&s 'hown on Drawing
3
#esultant ondition 0nner %oundary $a;imum 0nscribed Diameter
2 Positional -olerance =one at "$
5
-rue 3%asic5 Position of 7eature Ether Possible (;treme "ocations %oundary of "$ feature 'hown at (;treme "imit
-rue 3%asic5 Position of 7eature
&;is "ocation of "$ 7eature 'hown at (;treme "imit
'alculat%n& "esultant 'ond%t%on 3(;ternal 7eature5 16.+
"$ 'i>e of 7eature
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