GD&T

PROCEDURE / DRAFTING

FNHA-3-B-072.00

GEOMETRIC DIMENSIONING AND TOLERANCING 1.0

INTRODUCTION

1.2.2

ISO 1101

1.1

SCOPE

1.3

INDEX

This standard specifies and describes the principles of geometric dimensioning and tolerancing as applied to engineering drawings.

Index to the various sections can be found on page two. 1.4

1.2

REPLACED STANDARDS

REFERENCES

The following standards were used as reference to establish this standard.

This standard replaces the following company standard: Ford New Holland

WS 49.06

1.2.1 .2.1 ANS NSII Y14.5M .5M

NAME

STD GEO DIM & TOL ENGINEERING SPECIFICATION

ALL

C

TD

111649

9 8 03 1 0

ALL

B

EDF

110394

97 0 7 23

THE INFORMATION HEREON IS THE CONFIDENTIAL

REL

A

EDF

104739

9 5 01 2 3

AND PROPRIETARY PROPERTY OF NEW HOLLAND

FRAME NO.

REV

BY

ECN NO.

DATE

NORTH AMERICA, INC. AND/OR NEW HOLLAND

APP.

DRAWN

TD

MAR 1998

CANADA,, LTD. ANY USE, EXCEPT THAT FOR CANADA

FRAME

OF

1 PART NUMBER

86508251

69


FNHA-3-B-072.00

INDEX Section

Title

Page

1.

Symb mbo ology.. logy.... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .. 3 1.1 1.1

Geom Geomet etri ric c Char Charac acte teri rist stic ics s and and Symb Symbol ols s .... ...... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... 3

1.2 1.2

Othe Otherr Sy Symb mbol ols s (Re (Rela lati ting ng to Geom Geomet etri ric c Tol Toler eran anci cing ng)... )..... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .. 3

1.3 1.3

Iden Identi tify fyin ing g the the Tole Tolera ranc nce e Zone Zone.. .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .. 6

1.4

Fea Feature ture Co Contro trol Fra Frame & Da Datum tum Fea Feature ture Sy Symb mbo ol Pla Placeme cemen nt .... ...... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... 7

1.5 1.5

Use Use of No Note tes s .... ...... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... 7

2.

Datu Da tum m Refere feren ncing. cing... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... ..... 8 2.1 2.1

Datu Da tum m & Da Datu tum m Feat Featur ure e .... ...... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... 8

2.2 2.2

Refe Re fere renc ncin ing gD Dat atum ums s Acc Accor ordi ding ng to Impo Import rtan ance. ce... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... 10

2.3 2.3

Datu Da tum m Targ Target ets s .... ...... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... ..... ..... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... ..... ... 16

3.

Tol Toleran rances ces of Form Form.. .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... 21 3.1 3.1

Stra Straig ight htne ness ss Tole Tolera ranc nce e .... ...... .... ..... ..... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .. 21

3.2 3.2

Flat Flatne ness ss Tole Tolera ranc nce e .... ...... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... 24

3.3 3.3

Circ Circul ular arit ity y (Rou (Round ndne ness ss)) Tole Tolera ranc nce.. e.... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .. 25

3.4 3.4

Cyli Cylind ndri rici city ty Tole Tolera ranc nce... e..... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... ..... ..... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .. 25

4.

Tol Toleran rances ces for for Profi rofile le Contro trol .... ...... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... 28 4.1 4.1

Prof Profilile e Tole Tolera ranc nce.. e.... .... .... .... .... .... .... ..... ..... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... ..... ..... .... .... .... .... .... .... .... .... .... .... .... .... .... .... 28

5.

Tol Toleran rances ces for for Orie Orien ntati tatio on Contr ontro ol .... ...... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .. 35 5.1 5.1

Angu Angula lari rity ty Tole Tolera ranc nce e .... ...... .... .... .... .... .... .... .... .... .... .... .... .... .... .... ..... ..... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... ..... ..... .... .... 35

5.2 5.2

Para Parall llel elis ism m Tole Tolera ranc nce e .... ...... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... 38

5.3 5.3

Perp Perpen endi dicu cula lari rity ty Tole Tolera ranc nce e .... ...... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... 41

6.

Tole Tolera ranc nce es for for Runou nout Contr ontro ol ... ....... ...... .... .... .... .... ........ ...... .... .... .... .... ........ ...... .... .... .... .... .... .... .... .... .... .... .... .... ........ ...... .... .... .... .... ........ ...... .... .... .... 47 6.1 6.1

Circ Circul ular ar Ru Runo nout ut Tole Tolera ranc nce e .... ...... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .. 47

6.2 6.2

Tota Totall Ru Runo nout ut Tole Tolera ranc nce e .... ...... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .. 47

7.

Tol Toleran rances ces of Loc Locatio tion... n..... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... 52 7.1 7.1

Posi Positi tion on Tole Tolera ranc nce e .... ...... .... .... .... .... .... .... .... .... .... .... .... .... .... ..... ..... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... ..... ..... .... .... .... .... .. 52

8.

Fre Free Stat State e Vari Varia atio tion... n..... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... 68 8.1 8.1

Spec Specif ify ying ing C Cir ircu cula lari rity ty in a Free Free Stat State e with ith Aver Averag age e Diam Diamet eter er.. .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .. 68

8.2 8.2

Spec Specif ify ying ing Rest Restra rain intt for Non Non-r -rig igid id Par Parts ts .... ...... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .. 69

NAME

PART NUMBER

STD GEO DIM & TOL


FNHA-3-B-072.00

SYMBOLOGY 1. SYMBOLOGY. Wherever possible, the use of internationally accepted symbols is recommended rather than the use of notes. This eliminates the translation of notes into other other languages and also eliminates the possibility possibility of misinterpretation of the note. note. This section establishes the symbols for specifying specifying geometric characteristics and other other dimensional requirements on engineering drawings in accordance with ANSI Y14.5M and ISO 1101. 1.1 1.1

GEOM GEOMET ETRI RIC C CH CHAR ARAC ACTE TERI RIST STIC ICS S AN AND D SYMB SYMBOL OLS S TYPE OF TOLERANCE

FOR INDIVIDUAL

SYMBOL

FORM

FEATURES

FOR INDIVIDUAL OR

PROFILE

RELATED FEATURES

ORIENTATION FOR RELATED FEATURES

RUNOUT

LOCATION

STRAIGHTNESS

REFER TO 3.1

FLATNESS

3 .2

CIRCULARITY (ROUNDNESS)

3.3

CYLINDRICITY

3.4

PROFILE OF A LINE

4.1.2

PROFILE OF A SURFACE

4.1.2

ANGULARITY

5.1

PERPENDICULARITY

5.3

PARALLELISM

5.2

CIRCULAR RUNOUT

6.1

TOTAL RUNOUT

6.2

POSITION

7 .1

CONCENTRICITY *

——

CHARACTERISTIC

* THIS CHARACTERISTIC WILL NOT BE USED BY NEW HOLLAND

1.2 1.2

OTHER OTHER SYMB SYMBOL OLS S (REL (RELATI ATING NG TO GEOM GEOMETR ETRIC IC TOLER TOLERAN ANCI CING NG)) REFER TO OR

M S P

DATUM FEATURE SYMBOL

1.2.1

DATUM TARGET SYMBOL

1.2.2

FEATURE CONTROL FRAME

1.2.3

DIAMETER (CYLINDRICAL TOLERANCE ZONE WHEN USED WITH FEATURE CONTROL SYMBOL)

1.3

MAXIMUM MATERIAL CONDITION (MMC) **

1.2.4

REGARDLESS OF FEATURE SIZE (RFS)

1.2.5

PROJECTED TOLERANCE ZONE

1.2.6

BASIC (EXACT) DIMENSION ** FOR NEW HOLLAND APPLICATIONS UNLESS OTHERWISE SPECIFIED: POSITION TOLERANCE AND RELATED DATUMS APPLY AT MMC. OTHER GEOMETRIC GEOMETRIC TOLERANCES APPLY RFS. NEW HOLLAND WILL NOT USE THE SYMBOL ON DRAWINGS SINCE IT IS NOT INCLUDED IN THE ISO STANDARDS. S

NAME

PART NUMBER

STD GEO DIM & TOL

PROCEDURE / DRAFTING 1.2. 1.2.1 1

FNHA-3-B-072.00

Datu Da tum m feat featur ure e symb symbol ol

The datum feature symbol consists of a frame containing the datum identifying letter. The letter is preceded and followed by a dash. The symbol frame is associated to the datum feature by one one of the methods described in 1.4 for feature frames. Each datum feature requiring identification shall be assigned a different letter with the letters “I”, “O”, “Q”, and “X” omitted.

* 1.2. 1.2.2 2

MIN. 5 MM MIN. .2 IN

}

GRAPHIC DRAW INGS

MIN. 8 MM MIN. .3 IN

}

BOARD DRAW INGS

Dattum ta Da targe rget symb symbol ol

The datum target symbol is a circle divided divided horizontally into two halves. The lower half contains a letter identifying the associated datum, followed by the target number assigned sequentially starting with 1 for each datum.

Where the datum target area is a circular area, the area size may be entered in the upper half. Otherwise, the upper upper half is left blank.

Where the datum target is a point, the location is indicated by an “x” and the other half of the datum target symbol is left blank.

1.2.3 Feature 1.2.3 Feature control control frame. frame. Geometric Geometric characte characteristic ristic symbo symbols, ls, the tolera tolerance nce value, value, and and datum datum reference reference letters, letters, where applicable, are combined in a feature control frame to express a geometric tolerance.

A geometric tolerance for an individual feature is specified by means of a feature control frame divided into compartments containing the geometric characteristic symbol followed by the tolerance.

MM

*

MIN. 5 MM GRAPHIC BOARD MIN. .2 IN

MIN. 8

}

DRAW INGS

MIN. .3 IN

}

DRAW INGS

Where applicable, the tolerance is preceded by the diameter symbol and followed by the maximum material condition symbol.

NAME

PART NUMBER

STD GEO DIM & TOL


FNHA-3-B-072.00

Feat Featur ure e cont contro roll frame frame (co (cont ntin inue ued) d)

Where a geometric tolerance is related to a datum, this relationship is indicated by entering the datum reference letter in a compartment following the tolerance.

Where a datum is established by two datum features (for example, an axis established by two datum diameters) both datum reference letters, separated by a dash, are entered in a compartment.

Where more than one datum is required, the datum reference letters are entered into separate compartments in the desired order of precedence.

Datum reference letters need not be in alphabetical order in the feature control frame.

A composite feature control frame is used where more than one tolerance is specified for the same geometric characteristic of a feature f eature or features having different datum requirements.

Where a feature or pattern of features controlled by a geometric tolerance also serves as a datum feature, the feature control frame and datum feature symbol are combined.

1.2. 1.2.4 4

Maxi Ma ximum mum ma mate teri rial al con condi diti tion on (MM (MMC) C)

The maximum material condition symbol is specified in a feature control frame when the tolerance value is applied to the maximum material condition of the associated feature. h = T EXT HEIGHT IN FEATURE CONTROL FRAME

NAME

PART NUMBER

STD GEO DIM & TOL


FNHA-3-B-072.00

1.2.4.1 Effect of maximum 1.2.4.1 maximum material material condition. condition. Where a geometri geometric c tolerance tolerance is applied applied a MMC, MMC, the the tolerance tolerance is limited limited to to its specified value if the feature is produced at its its MMC limit of size. If the actual size of the feature feature is not its MMC, then then the allowable tolerance will increase equal to the difference between the feature’s actual size size and its MMC. This principle also applies to a datum feature if it is referenced at MMC. MMC. The axis or centerplane of the datum feature may deviate from the axis or center plane of its datum by an amount equal to the difference between its actual size and its MMC. 1.2.4.2 Position tolerance and its related datums will apply at MMC unless otherwise specified. It is not required to show the the symbol symbol in the feature control frame frame for this application application since this note note is specified in the general general tolerance tolerance M block on all drawings. 1.2.5 1.2.5 Regardless Regardless of feature feature size (RFS). (RFS). The symbol symbol will not be used on drawings drawings since it is not an accepted accepted S worldwide symbol and may be eliminated. 1.2.5.1 Effect of RFS. Where a geometric 1.2.5.1 geometric tolera tolerance nce is applied applied on a RFS RFS basis, basis, the toleran tolerance ce is limited limited to its specifie specified d value regardless of the actual size size of the feature. Likewise, referencing a datum feature on on a RFS basis means that a centering about its axis or center plane is required, regardless of the actual size of the feature. 1.2.5.2 RFS applies 1.2.5.2 applies to the geometric geometric tolerance, tolerance, datum datum reference reference or both where where no material material condition condition is specified specified unless otherwise specified in the general tolerance block on the drawing. 1.2. 1.2.6 6

Proje roject cte ed to tolera leran nce zone one

Where a projected tolerance zone is applied to a position or orientation tolerance, a frame containing the projected tolerance zone symbol preceded by the zone height is placed below the feature control frame.

1.3 1.3 IDEN IDENTI TIFY FYIN ING G THE THE TOLE TOLERA RANC NCE E ZONE ZONE.. The The diam diamet eter er symb symbol ol ∅ will precede the tolerance value where the tolerance value represents represents the diameter of a cylindrical zone. No identification symbol is required where the tolerance zone is other than a diameter, as this tolerance value represents the distance between two parallel lines or planes, or the distance between two uniform boundaries.

NAME

PART NUMBER

STD GEO DIM & TOL


FNHA-3-B-072.00

1.4 FEATURE FEATURE CONTROL CONTROL FRAME FRAME AND DATUM DATUM FEAT FEATURE URE SYMBOL SYMBOL PLACEM PLACEMENT. ENT. To rela relate te the the ffeat eature ure contro controll frame and datum feature symbol to its associated feature, use one of the following methods. (a)

Add the featu feature re control control frame or or datum datum feature feature symbol symbol below or after after a leader-dire leader-directed cted callout callout or or dimension dimension directed to the feature.

(b)

Use a leader leader from from the feature feature control control frame frame or datum datum featur feature e symbol symbol to the the feature. feature.

(c)

Locate Locate a side or end of the feature feature control control frame frame or datum datum feature feature symbo symboll on an extension extension line line from the the feature if the feature is a plane surface.

(d)

Locate Locate a side or end end of the featu feature re control control frame frame or datum datum feature feature symbol symbol on an extensi extension on line of the the dimension line relating to a feature of size.

1.5 USE OF NOTES NOTES.. Situat Situation ions s may arise arise in in which which the the geome geometri tric c requir requireme ement nt desire desired d cannot cannot be to total tally ly defi defined ned by by use of symbols. In these situations a note may be used, either separately or to supplement a symbol, to describe the requirement.

NAME

PART NUMBER

STD GEO DIM & TOL


FNHA-3-B-072.00

DATUM REFERENCING 2. DATUM DATUM REFE REFEREN RENCIN CING. G. Where the geo geomet metric ric tolera tolerance nce requir requiremen ementt of a featu feature re is is relat related ed tto o anoth another er feat feature ure or features, a datum reference is used. This section defines methods of establishing those datums and the the interpretation of them. 2.1

DATUM AND DATUM FEATURE

Surfaces of parts produced by normal manufacturing methods will, if magnified, have have some irregularity in the surface. The actual part surface designated is the datum feature and the true geometric counterpart of that surface establishes the datum. The datum is the the origin of the dimensional relationship between the toleranced feature and the related feature.

2.1.1 Datum ffeatur 2.1.1 eature e selection. selection. Datu Datum m features features are are selected selected to to control control the the relations relationship hip betwee between n features features of of a part to insure proper fit, function, and assembly assembly of parts. Where practical, corresponding features on mating or related related parts should be selected as datum features. A datum feature should be accessible on the part part and be of sufficient size for practical usage. 2.1.2. 2.1. 2.

Datums Datums are used, used, as applicabl applicable, e, to control control profile, profile, orientatio orientation, n, runout, runout, and and location. location. Refer to to 1.1.

2.1. 2.1.3 3

Datu Datum m fea featu ture re symb symbol ol plac placeme ement nt

Application to a plane surface

Where a plane surface is to be used as a datum feature, f eature, the datum feature symbol is located on an extension line directed to the surface or by a leader line directed to to the surface. When using a triangle on an extension line to designate a plane surface, the triangle should not be centered on a dimension line.

NAME

PART NUMBER

STD GEO DIM & TOL

PROCEDURE / DRAFTING 2.1.3 2.1 .3

FNHA-3-B-072.00

Datum Dat um feat feature ure symbo symboll plac placeme ement nt (conti (continue nued) d)

Application to a feature of size

Where the datum feature is a feature of size, whether a cylindrical surface or two parallel planes, the datum feature symbol must be clearly related to the size dimension or to the feature. When using a triangle to designate a feature of size, the triangle must be centered on the dimension line.

Partial surfaces as datum features For some design requirements, only a portion of a surface is required to be designated as a datum feature. In these situations, a chain line located by basic dimensions is used to identify that portion of the surface.

NAME

PART NUMBER

STD GEO DIM & TOL


FNHA-3-B-072.00

2.1.4 Compound 2.1.4 Compound d datum atum features. features. Two datum datum features features may may be u used sed to to establish established ed a single single da datum. tum. To accomplish accomplish this, each datum feature or portion of datum datum feature is designated with its own datum datum feature symbol. The datum reference letters, separated by a dash, are then shown in a single compartment of the feature control frame. A single datum plane can be established by simultaneously contacting the high points of two surfaces.

A single datum axis for two coaxial diameters can c an be established by simultaneously contacting the high points of both surfaces.

2.2 REFERE REFERENCI NCING NG DATU DATUMS MS ACCO ACCORDI RDING NG TO IMPORTA IMPORTANCE NCE.. A featu feature re can can b be e refer referenc enced ed tto o up to thre three e plane plane surfaces simultaneously if required. When this is done, and order of precedence must be defined in the feature feature control frame according to the importance of each plane to the toleranced feature. This first datum referenced is the most important or primary datum. datum. The second datum referenced is the secondary datum and the third datum datum referenced is the tertiary datum. Refer to 1.2.3. Datum reference frame

NAME

PART NUMBER

STD GEO DIM & TOL


FNHA-3-B-072.00

2.2.1 Positionin 2.2.1 Positioning g a part on a datum datum referenc reference e frame. frame. A part positioned positioned on a datum datum referen reference ce frame must contact contact the primary datum plane at a minimum of three points, the secondary datum plane at a minimum of two points, and the tertiary datum plane at a minimum of one point. Shown below is a part with two ∅77..20 holes which must be located within ∅0.2 at MMC to a primary (D), secondary (E) and tertiary (F) datum. To satisfy this geometric tolerance requirement, the finished part, when dropped over two ∅6.8 (∅7.0 MMC-0.2 total tol.) pins, must contact datum plane D a minimum of three points, datum plane E a minimum of two points, and datum plane F a minimum of one point.

Shown below is an inspection fixture that would check this part according to the specified geometric tolerance.

NAME

PART NUMBER

STD GEO DIM & TOL


FNHA-3-B-072.00

2.2.2 Positionin 2.2.2 Positioning g parts parts with a cylindri cylindrical cal datum datum feature feature on a reference reference frame. The datum datum establishe established d by a cylindric cylindrical al surface is the axis of a true cylinder as established by inspection inspection equipment. A cylindrical datum feature is always associated with two theoretical planes intersecting intersecting at right angles on a datum axis: therefore, a cylindrical datum feature uses two of the planes on a datum reference frame. . Shown below is a part with four ∅112 10.8 holes which must be located within ∅0.8 at MMC to a primary (K) and secondary (M) datum. To satisfy this geometric tolerance requirement, requirement, the finished part, when when dropped over four ∅10 (∅10.8 MMC0.8 total tol.) pins, must contact datum plane K a minimum of three points and must fit within a ∅76.4 (MMC) datum M boundary.

Shown is an inspection fixture that would check this part according to the specified geometric tolerance.

NAME

PART NUMBER

STD GEO DIM & TOL


FNHA-3-B-072.00

2.2.3 Angular 2.2.3 Angular orientat orientation. ion. Where it is important important to establish establish the the angular angular orienta orientation tion of of a part part about about the datum datum axis, axis, a tertiary datum feature is referenced in the feature control frame. In the example shown below, angular orientation of the two planes intersecting through datum B is established by the center plane of slot C, the tertiary datum feature.

The illustration below shows the development of the theoretical datum reference frame for the position tolerance shown above.

NAME

PART NUMBER

STD GEO DIM & TOL


FNHA-3-B-072.00

2.2.4 Effect of datum 2.2.4 datum sequence sequence and and material material condit condition. ion. Where datums datums specifie specified d in sequence sequence include include a feature feature of size, size, the material condition at which the the datum feature applies must be determined. The effect of its material condition and order of precedence should be considered relative to the fit and function of the part. As previously stated, position tolerances and their related datums will apply at MMC unless otherwise otherwise specified. Other geometric tolerances will apply RFS unless otherwise specified. The illustration below shows the different effects that changing the material condition of the datum features and the sequence of the datum references has on the allowable finished part.

NAME

PART NUMBER

STD GEO DIM & TOL


FNHA-3-B-072.00

2.2.4.1 Datum features designated designated RFS. Where a datum feature feature of size is designated as as RFS, the datum is determined determined by physical contact between the surface or surfaces of the feature and inspection tools.

NAME

PART NUMBER

STD GEO DIM & TOL


FNHA-3-B-072.00

2.2.4.2 Datum features designated designated MMC. MMC. Where a datum feature of size is designated at at MMC, the datum is the equivalent of the MMC limit of size of the datum feature. 2.3 DATUM DATUM TARGETS TARGETS.. Due tto o distor distortio tion n cause caused d by weldi welding, ng, forming forming,, castin casting, g, etc. etc.,, the the entire entire surf surface ace of some some features cannot be used effectively effectively to establish a datum. Where this condition arises, the important points, lines, lines, or areas of contact of that feature should be be used to define the datum for that feature. feature. These points, lines, or areas are called datum targets. 2.3. 2.3.1 1

Datu Datum m tar targe gett sym symbo bols ls (Ref (Refer er to 1.2. 1.2.2) 2)

Datum target points The symbol “X” is used to indicate a datum target point on a surface. The “X” is located by dimensions on a direct view of the surface, or where there is no direct view it is located on two edge views.

Datum target lines A datum target line is indicated by the symbol “X” on an edge view of the surface and a phantom line on the direct view. Where the length of the datum target line must be controlled, its length is dimensioned in the direct view.

NAME

PART NUMBER

STD GEO DIM & TOL


FNHA-3-B-072.00

Datu Datum m targ target et sy symbols mbols (co (cont ntin inue ued) d)

Datum target areas Where it is necessary to designate areas of flat contact rather than points to assure proper establishment of a datum, a target area of the desired shape shape is specified. The datum target area is indicated by section lines inside a phantom outline of the desired shape. If the datum target area is a diameter, diameter, its size may be specified in the upper upper half of the datum target symbol; otherwise, otherwise, the desired shape is controlled by dimensions on the drawing. Where a circular target area is too small to show it on the drawing. it may be represented by an “X” and its diameter specified in the datum target symbol.

Single datum target areas (partial datums) In some situations, one datum target area is of sufficient size to be used to determine the datum and is also the only area of the surface that is important when referenced referenced to a geometric tolerance. In such instances, that target target area is shown and dimensioned on the drawing. The symbol should be used to designate it.

NAME

PART NUMBER

STD GEO DIM & TOL


FNHA-3-B-072.00

2.3.2 2.3. 2 Datum p planes lanes created created by datum datum targets. targets. A primary primary datum datum plane plane is establ established ished by by at least three three target target points points or or areas not on a straight line or by at least three points of contact within a single datum target area. Secondary datum planes are established by two target points or areas, and tertiary datum planes are established by one target point or area. The illustration below shows the establishment of a primary datum plane from three datum target areas.

2.3.3 Dimensioning 2.3.3 Dimensioning datum datum targets. targets. Locating Locating dimension dimensions s and size size dimensio dimensions, ns, where where require required, d, can be expressed expressed in the form of either basic dimensions or toleranced dimensions. Where basic dimensions are used, tooling or gaging tolerances are assumed to apply. The illustration below shows three perpendicular planes established by three points on the primary datum feature, two points on the secondary datum feature, and one point of the tertiary datum feature.

NAME

PART NUMBER

STD GEO DIM & TOL

PROCEDURE / DRAFTING 2.3.4 2.3. 4

FNHA-3-B-072.00

Step datums. datums. A datum datum p plane lane may be e establ stablished ished by targets targets located located on steppe stepped d surfaces surfaces

In the illustration below, a basic (gage) dimension defines the offset off set between the target points while a toleranced dimension controls the distance between the surfaces.

2.3.5 Circular 2.3.5 Circular target target lines lines and cylindr cylindrical ical target target areas. areas. On rotating rotating cylindri cylindrical cal parts, parts, it is sometimes sometimes necess necessary ary to to apply the geometric tolerance for a feature to only a portion of or circular line on a cylindrical datum surface. In these situations, a circular target line or cylindrical cylindrical target area should be designated. designated. An example of this would be the bearing area area of a shaft.

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2.3.6 Restrainin 2.3.6 Restraining g of parts parts to a datum datum plane. plane. Restrainin Restraining g is the the applicatio application n of a force force to the free free state state conditio condition n of a part part in order to simulate its actual assembled condition. In some situations, it is important to to tolerance a feature of a part to the the part’s restrained condition rather than its free state condition. This is accomplished by adding a note to the feature control frame.

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TOLERANCES OF FORM 3. TOLERAN TOLERANCES CES OF FORM FORM.. This sectio section n defi defines nes the met method hods s of dimensi dimensioni oning ng and tolera toleranci ncing ng to contro controll the the form form of a feature or element of a single feature. Since form tolerances apply only to a single (individual) feature or element element of a single feature, they are not related to datums. datums. The geometric form characteristics are straightness, flatness, flatness, roundness (circularity), and cylindricity. cylindricity. (Refer to 1.1) 3.1 STRAIGH STRAIGHTNES TNESS S TOLERA TOLERANCE NCE.. Straig Straightn htness ess is is a condit condition ion w wher here e an eleme element nt of of a surfac surface e or an an axis axis is a stra straigh ightt line. A straightness tolerance tolerance specifies a tolerance tolerance zone within within which the considered element or axis must lie. The straightness tolerance is shown in the view where the elements to be controlled appear as a straight line. 3.1.1 3.1 .1

Straig Straightn htness ess — indivi individua duall line line elemen elements ts

A straightness tolerance directed by a leader to the surface of the feature f eature controls individual line elements of the surface. This control requires each line element to be within two parallel straight lines, separated by the specified tolerance.

Example

In the example to the right, each line element of the surface must lie within two parallel lines (0.02 apart) where the two lines li nes and the nominal axis share a common plane. The feature must always always be within the specified limits of size and the boundary of perfect form at MMC. The allowable deviation from straightness will become less than the specified straightness tolerance (for example, when the actual size of the feature is ∅19.99, the straightness deviation is 0.01 maximum).

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Stra Straig ight htne ness ss — axis axis cont contro roll

A straightness tolerance directed to a size dimension, either by attachment to the dimension line or by placement immediately adjacent to the dimensional value, controls the straightness of the axis of the feature. This control requires the axis of the feature to to lie within a cylindrical tolerance zone zone equal in diameter to the tolerance. tolerance. This method permits the straightness tolerance to exceed the MMC limit of size.

Example — straightness of a feature of size — RFS (recommended)

Where a straightness tolerance is applied to a feature of size RFS, the axis or centerline of the actual feature size must lie within the specified cylindrical tolerance zone ( ∅0.04). Additionally, each circular element element of the surface must be within the specified specified limits of size. NOTE — Straightness tolerance always applies RFS unless otherwise specified.

Example — straightness of a feature of size — MMC

Where a straightness tolerance is applied to a feature of size at MMC, the axis or centerline of the actual feature must lie within the specified cylindrical tolerance zone ( ∅0.04) at MMC. As the feature departs from MMC, the allowable straightness tolerance increases equally to the the feature’s departure from MMC. MMC. See the chart for examples. Additionally, each circular element of the surface must be within the specified limits of size.

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3.1.3 Straightn 3.1.3 Straightness ess — unit unit length length and total. total. In order order to prevent prevent an an abrupt abrupt surface surface variatio variation n over a relativ relatively ely short short length length of a feature, a straightness tolerance tolerance may be applied on a unit basis. When using unit control, a maximum straightness tolerance for the feature should always be specified because of the large variation that could occur if not controlled c ontrolled overall. Example — straightness per unit length and total — RFS

In this example, the diameter of the tolerance zone over any 20 mm length of the feature is 0.01 while the diameter of the tolerance zone over the total length of the feature is 0.04. Additionally, each circular element of the the surface must be within the specified limits of size.

3.1. 3.1.4 4

Stra Straig ight htne ness ss — pla plane ne surf surfac aces es

Straightness may be applied to control line elements in a single direction or two two directions on plane surfaces. It is designated by a leader line in a direct view of the surface that shows the direction the the tolerance is to be applied. In this example, each longitudinal element of the surface must lie between two parallel lines 0.05 apart in the left view and 0.1 in the right view.

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3.2 FLATNES FLATNESS S TOLERAN TOLERANCE. CE. A flatne flatness ss toler toleranc ance e define defines s the perm permitt itted ed devia deviatio tion n of a surfa surface ce from from a theor theoreti etical cally ly flat plane. The feature control frame for a flatness tolerance is attached to a surface by either a leader line directed to the surface or by locating it on an extension line to the surface.

Example

In this example all the surface variation must lie within two parallel planes separated by the specified flatness tolerance (0.08). If the surface is associated with a size dimension, the flatness tolerance may not exceed the size tolerance.

3.2.1 3.2. 1 Flatness Flatness — unit unit area area and ttotal otal.. In order order to preven preventt an abrupt abrupt surfac surface e variation variation in a relativ relatively ely small small area area of a feature, a flatness tolerance may be applied on a unit basis. When using unit control, as flatness tolerance for the entire feature should also be specified because of the large variation that could occur if not controlled overall. Example In the feature control frame to the right, any 30 ×30 area of the surface it is directed to would have to lie between two parallel planes. 0.1 apart, and the entire surface would have to lie between two parallel planes 0.4 apart.

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3.3 ROUNDNE ROUNDNESS SS (CIRC (CIRCULA ULARIT RITY) Y) TOLER TOLERANC ANCE. E. A roundn roundness ess tole toleran rance ce defin defines es the the p permi ermitt tted ed devi deviati ation on of of any circular element of a feature from a theoretically true circle. Any circular element must lie between between two concentric circles whose radius difference is equal to the specified tolerance. Example

In this illustration, each circular element of the surface must lie within two concentric circles, one having a radius 0.25 greater than the other. Additionally each circular element of the surface must be within the specified limits of size. Also, the roundness roundness tolerance may not exceed the size tolerance.

3.4 CYLINDRIC CYLINDRICITY ITY TOLERANCE. TOLERANCE. A cylindr cylindricity icity tolerance tolerance defines defines the permitted permitted deviation deviation of any any circular circular element element of of a cylindrical feature from a theoretically perfect cylinder. cylinder. Any circular element of the feature must lie between two concentric cylinders whose radius difference is equal to the specified tolerance. Example

In this illustration, the cylindrical surface must lie between two concentric cylinders, one having a radius 0.25 larger than the other. Additionally, the surface must be within the specified lim its of size. Also, the cylindricity tolerance may not exceed the size tolerance.

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STD GEO DIM & TOL

PROCEDURE / DRAFTING 3.5 3.5

FNHA-3-B-072.00

EXAM EXAMPL PLES ES WITH WITH FOR FORM M TOL TOLER ERAN ANCE CES S APP APPLI LIED ED

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EXAM EXAMPL PLE E WITH WITH FOR FORM M TOLE TOLERA RANC NCES ES AN AND D RUN RUNOU OUT T TOLE TOLERA RANC NCES ES APPL APPLIE IED D

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TOLERANCES FOR PROFILE CONTROL 4. TOLERAN TOLERANCES CES FOR PROFILE PROFILE CONTROL CONTROL.. This sectio section n def define ines s meth methods ods of dimensi dimensioni oning ng and tolera toleranci ncing ng to control the profile (outline) of a part part or portion of a part. This control can be applied to either a single line element on on the profile surface or to the entire surface. 4.1 PROFIL PROFILE E TOLERAN TOLERANCE. CE. A profi profile le toler toleranc ance e define defines s a toler toleranc ance e zone zone cont control rollin ling g the the form form of line line e eleme lements nts or or surfaces of a part outline or portion of a part part outline as related to its own perfect perfect counterpart. This control can be applied to a related datum if applicable. 4.1. 4.1.1 1

Appl Applic icat atio ion n of pro profil file e tole tolera ranc nces es

Dimensions Basic dimensions are used to dimension the outline or portion of the outline to which profile tolerances tolerances apply. These basic dimensions represent the true geometric shape to which the profile tolerance is applied. applied. Where there are many basic dimensions, the note “untoleranced dimensions are basic” may be used and the boxes around the dimensions may be omitted.

Line element control A line profile tolerance directed by a leader to the part outline controls individual line elements of the part outline on the part surface.

Total surface control A surface profile tolerance directed by a leader to the part outline controls the total surface of the part outline. All around or between points

Where the profile tolerance applies to the entire part periphery, the symbol ∅ is applied to the leader. See (a). If the tolerance applies applies to only a portion of the part periphery, it should be designated as shown in (b).

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Applic Applicati ation on o off profi profile le tole toleran rances ces (con (contin tinued ued))

Profile tolerance — no datum reference Where profile tolerancing is used only for feature form control, no datum reference is specified. This indicates that the the feature is to be compared to its perfect counterpart without any positioning to a datum.

Profile tolerance with datum reference

Where a profile tolerance for a feature or features is related to another feature, that other other feature should be specified as a datum. This requires the tolerance zone to be fixed in orientation to that datum.

Bilateral tolerance zone

Where no indication of tolerance zone is shown on the drawing, the profile tolerance is understood to be a bilateral bilateral tolerance. This means that the tolerance zone is centered on the perfect profile of the feature or features.

Unilateral tolerance zone

Where the tolerance zone is to apply to either one side or the other of the perfect profile, the zone is indicated by a phantom line adjacent to the side s ide of the profile that the tolerance zone is to be on and by arrowheads indicating the zone. The phantom line should be drawn parallel to to the profile and need only be long enough to clearly indicate to which side of the profile the tolerance must be.

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Interp Interpret retati ation on of profile profile tolera tolerance nces s

Profile of a line element

Where a line profile tolerance is specified, any line element of the designated surface must lie within the specified s pecified tolerance zone (0.3).

Profile of a surface

Where a surface profile tolerance is specified, the entire surface that is designated must lie within the specified tolerance zone (0.3).

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Profile Profile tolera tolerance nces s in in part part app applica licatio tions ns

Profile toleranced surface located by a toleranced dimension

Where a profile toleranced surface is located by a toleranced dimension only, the profile tolerance zone (0.3) may lie anywhere within the tolerance zone established by the locating dimension (±1). The actual surface profile must lie within the profile tolerance zone (0.3).

Profile toleranced surface located by a toleranced dimension and related datum

Where a profile toleranced surface is located by a toleranced dimension and referenced to a datum, the profile tolerance zone (0.3) may lie anywhere within the tolerance zone established by the locating dimension ( ±1) but must maintain its orientation to the referenced datum ( ). The actual surface profile – A – must lie within the profile tolerance zone (0.3).

Profile tolerance for coplanar surfaces

Where two or more surfaces have all their elements in one plane, the flatness of that total plane can be controlled by a surface profile note. The profile tolerance establishes a tolerance zone (0.1) defined by two parallel planes within which all elements of the indicated surfaces must lie.

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Profile Profile tole toleran rances ces in part part appl applica icatio tions ns (cont (continu inued) ed)

Profile toleranced surface located by a basic dimension to datum surface Where a profile toleranced surface is located by a basic dimension, the profile tolerance can be applied either bilaterally or unilaterally.

Where a bilateral profile tolerance is applied to a feature or features, the tolerance zone (0.3) is equally disposed about the true profile of the designated surface at the basic dimension.

Where a unilateral profile tolerance is applied to a feature or features, the tolerance zone (0.3) is all located to either the outside or inside of the true profile of the designated surface at the basic dimension.

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Profile tolerance all around

Where a profile tolerance is applied all around (∅), the tolerance can be applied bilaterally or unilaterally (the illustration shows a bilateral tolerance). The actual outside outside surface profile must lie within the specified tolerance zone (0.8).

Where it is necessary to relate the tolerance zone to another surface, that surface can be specified as a datum.

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Profile tolerances to control alignment Where two or more parts are shown to align in a weld assembly or assembly, the allowable misalignment (determined by design and function) can be one of three three conditions. Bilateral and unilateral profile tolerances tolerances can be used to express these allowable conditions.

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TOLERANCES FOR ORIENTATION CONTROL 5. TOLERAN TOLERANCES CES FOR ORIENT ORIENTATI ATION ON CONTROL CONTROL.. This sectio section n def define ines s met method hods so off tole toleran rancin cing g to contro controll the orientation of features features to other features. The orientation tolerances tolerances are angularity, angularity, perpendicularity, perpendicularity, and parallelism. They may also be referred to as attitude tolerances. When specifying orientation tolerances, the considered feature is related to one or more datum features. Orientation tolerances apply apply RFS unless otherwise specified. 5.1 ANGULA ANGULARIT RITY Y TOLERA TOLERANCE NCE.. Angula Angularit rity y is the the condi conditio tion n of a surfa surface ce or axis axis at a specif specified ied angl angle e (other (other than than 90º) 90º) from a datum plane or axis. The angularity tolerance tolerance is the distance between two two parallel planes, inclined at the the specified angle to a datum plane or axis, within which the tolerance surface or axis must li e. 5.1. 5.1.1 1

Appl Applic icat atio ion n of angu angula lari rity ty con contr trol ol

Angularity for a plane surface Where an angularity toleranced surface is located by a toleranced dimension, the angularity tolerance zone (0.3) may lie anywhere within the tolerance zone established by the dimension, but must maintain its relationship to the referenced datum ( ). The actual profile of the surface must lie within the angularity tolerance zone (0.3). – A –

Angularity for an axis (RFS) Where an angularity tolerance is applied to a feature of size, the axis or centerplane of that feature of size may lie anywhere within the tolerance zone (0.5) established by the angularity tolerance in relationship to the referenced datum.

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FNHA-3-B-072.00

Applic Applicati ation on of ang angula ularit rity y contr control ol (cont (continu inued) ed)

Loose control of angularity between features For drawing purposes, features are sometimes shown on the same centerline or at 90º when in actual function a liberal angular relationship is allowable between between those features. In such cases, the angular tolerance tolerance may be expressed in degrees instead of decimals. Position of these features in relation to the axis of the shaft is controlled by the standard shop practices manual: however, if a tolerance different from that specified in the standard shop practice manual is required, it must be specified in the form of an additional positional (!) tolerance.

No control of angularity between features.

Where the angularity between features may vary freely, a symbol may be used to designate that no angularity control is needed.

Angularity control between some features

On some parts the angularity between some features must be controlled while the angularity between between others may vary freely. This can be designated as shown.

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STD GEO DIM & TOL


FNHA-3-B-072.00

Applic Applicati ation on of ang angula ularit rity y contr control ol (cont (continu inued) ed)

No angularity control specified

Where features are located on centerlines and no angularity control is specified, the angular relationship between the features shall be ±1 º .

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5.2 PARALL PARALLELI ELISM SM TOLERA TOLERANCE NCE.. A parall paralleli elism sm tolera tolerance nce defin defines es the the permit permitted ted d devi eviati ation on from from a theoret theoretica ically lly exac exactt parallel condition. A parallel tolerance specifies:

A tolerance zone defined by two planes or lines parallel to a datum plane or axis within which the considered feature (axis or surface) must lie.

A cylindrical tolerance zone parallel to a datum axis within which the axis of the considered feature must lie.

5.2. 5.2.1 1

Appl Applic icat atio ion n of par paral alle leli lism sm cont contro roll

Parallelism tolerance defined by two planes

Where a parallelism tolerance for a surface or line is referenced to a datum surface, the designated line or surface must lie totally within the tolerance zone established by two parallel planes separated separated by the the specified tolerance. This tolerance zone in turn may lie anywhere within the size dimension of the part but must always remain parallel to the referenced datum.

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Applic Applicati ation on o off paral parallel lelism ism cont control rol (cont (continu inued) ed)

Parallelism tolerance defined by two planes (continued)

Where a parallelism tolerance for an axis is referenced to a datum surface, the designated axis must m ust lie totally within the tolerance zone established by two parallel planes separated by the specified tolerance. tolerance. This tolerance zone in turn may lie anywhere within the size dimension of the part but must always remain parallel to the referenced datum.

Parallelism tolerance defined by a cylindrical tolerance zone

Where a parallelism tolerance for an axis is referenced to a datum axis, the toleranced axis must lie totally within a cylindrical tolerance zone equivalent to the specified tolerance. This cylindrical tolerance zone in turn may lie anywhere within the size dimension of the part but must always remain parallel to the referenced datum.

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FNHA-3-B-072.00

Applic Applicati ation on o off paral parallel lelism ism cont control rol (cont (continu inued) ed)

Parallelism tolerancing at MMC (effect of MMC)

Where a parallelism tolerance is applied to a feature of size at MMC, the tolerance zone within which the axis or centerplane of the feature of size must lie is the specified tolerance when the feature feature of size is at its MMC. As the feature of size departs from its MMC, the tolerance zone increases; however, the tolerance zone still must lie within the size dimension of the part and must always remain parallel to the referenced datum.

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5.3 PERPENDICU PERPENDICULARITY LARITY TOLERANCE. TOLERANCE. A perpendicul perpendicularit arity y tolerance tolerance defines defines the permitted permitted deviation deviation of a surface, surface, axis, or centerplane from a theoretically theoretically exact 90º datum plane or axis. axis. A perpendicularity tolerance specifies:

A tolerance zone defined by two parallel planes perpendicular to a datum plane within which the surface of a feature must lie.

A tolerance zone defined by two parallel planes perpendicular to a datum plane within which the centerplane of a feature of size must lie.

A tolerance zone defined by two parallel planes perpendicular to a datum axis within which the axis of a feature of size must lie.

A cylindrical tolerance zone perpendicular to a datum plane within which the axis of a feature of size must lie.

A tolerance zone defined by parallel, straight lines perpendicular to a datum plane or datum axis within which an element of the surface must lie (radial perpendicularity.) perpendicularity.)

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Applic Applicati ation on of perpen perpendic dicula ularit rity y contro controll

Plane surface to a datum plane

Where a perpendicularity tolerance for a surface or line is referenced to a datum surface, the designated surface or line must lie totally within the tolerance zone established by two parallel planes separated by the specified tolerance and at 90º to the referenced datum. This tolerance zone zone must lie within the size dimension of the part.

Plane surface to two datum planes

Where a perpendicularity tolerance for a surface is referenced to two datum surfaces, the surface must lie within the specified tolerance zone perpendicular to each datum when the part is resting on at least three points on the primary datum plane and touching at least two points on the secondary s econdary datum plane. This tolerance zone zone must also lie within the size dimension of the part.

Feature of size (rect.) to a datum plane

Where a perpendicularity tolerance tolerance for a rectangular feature of size is referenced to a datum plane, the centerplane of that feature must lie within the tolerance zone established by two parallel planes separated by the specified tolerance and at 90º to the referenced datum. Also, the feature feature centerplane centerplane must be within the location dimension.

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Applic Applicati ation on of perpen perpendic dicula ularit rity y contro controll (contin (continued ued))

Feature of size to a datum axis

Where a perpendicularity tolerance tolerance for a cylindrical feature of size is referenced to a datum axis, the axis of that feature of size must lie within the tolerance zone established by two parallel planes separated by the specified tolerance and at 90º to the referenced datum axis. Also, the axis of the feature must lie within the location dimension.

NOTE: The perpendicularity ttolerance olerance does not control the intersection intersection of the feature axis and the datum axis. If this control is required, a position position tolerance should be used used instead. See 7.1.3. Perpendicularity for an axis at a projected height In some situations (holes for dowel pins, tapped holes for bolts, etc.) it may be necessary to control the axis of a hole for a distance beyond the datum surface equal to the thickness of the mating part. This is accomplished by specifying a perpendicularity tolerance at a projected projected height. The feature axis must lie within the specified cylindrical tolerance zone which is perpendicular to and projects from the referenced datum plane for the specified height. Also, the axis of the feature over the projected height must lie within the location dimension.

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Cylindrical feature of size to a datum plane

Where a perpendicularity tolerance for a cylindrical feature of size is referenced to a datum plane, the axis of that feature must lie within the specified cylindrical tolerance zone which is at 90º to the referenced datum datum plane. Also, the axis of the feature must lie within the location dimension.

Perpendicularity for a line element of a surface to a datum plane Where a perpendicularity tolerance is applied to any line element of a surface in relationship to a referenced datum plane, any line on that surface must lie within the specified tolerance zone which is perpendicular to the referenced datum plane. Also, any line element of the surface must lie within the location dimension. This approach can also be used to control perpendicularity of radial elements to a datum axis.

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Perpendicularity tolerancing at MMC (effect of MMC)

Where a perpendicularity tolerance tolerance is applied to a cylindrical feature of size at MMC and referenced to a datum plane, the axis of the feature must lie within a cylindrical tolerance zone zone that is perpendicular to to the datum plane. The diameter of the cylindrical tolerance zone is the specified perpendicularity tolerance tolerance when the feature is at its MMC. As the feature departs from its MMC, the diameter of the cylindrical tolerance zone increases accordingly.

Shown to the right is an inspection gage that would check this part.

5.4 CONTROL CONTROL OF FLATN FLATNESS ESS BY ORIENTA ORIENTATIO TION N TOLERA TOLERANCE NCES. S. Where an o orie rienta ntatio tion n toler toleranc ance e (angu (angular larity ity,, parallelism, or perpendicularity) is applied to a plane surface, the flatness of that surface is also controlled within the tolerance zone specified by the orientation orientation tolerance. An additional flatness tolerance is specified only where a more limiting flatness control of that surface is required.

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EXA EXAMPLES PLES WITH WITH ORI ORIEN ENTA TATI TION ON TOLE TOLER RAN ANCE CES S

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FNHA-3-B-072.00

TOLERANCES FOR RUNOUT CONTROL 6. TOLERAN TOLERANCES CES FOR RUN RUNOUT OUT CONTROL CONTROL.. This sectio section n defi defines nes met method hods s of of tole toleran rancin cing g to to cont control rol the runout runout of a feature or single element of a feature to another another feature or combination of features. features. The features controlled by runout runout tolerances are located located either around a datum axis or perpendicular perpendicular to a datum datum axis. A datum is always always required. The runout tolerances are circular runout runout (single element of a surface) and total runout runout (total surface). Runout tolerances always apply RFS. 6.1 CIRCUL CIR CULAR AR RUNOU RUNOUT T TOLERAN TOLERANCE. CE. A circul circular ar runo runout ut tole toleran rance ce speci specifie fies s the maximum maximum allow allowabl able e devia deviatio tion n from from perfect form of a line element of a surface as it rotates 360º about a datum axis. 6.2 TOTAL RUN RUNOUT OUT TOLER TOLERANC ANCE. E. A total total runo runout ut tole toleran rance ce speci specifie fies s the the maximu maximum m allowa allowable ble dev deviat iation ion from from perfec perfectt form of an entire surface as it rotates 360º about a datum axis. 6.3. 6.3.

ESTA ESTABL BLIS ISHI HING NG DAT DATUM UMS S FOR FOR MEAS MEASUR URIN ING G RUNO RUNOUT UT

Datums for measuring runout should be selected according to the function of the part. part. Generally for a shaft they will be the bearing diameters, since they determine the center of rotation of the shaft in actual application.

Where the shaft is supported by two bearings bearings on the same diameter, the datum for measuring runout should be designated by datum targets centered on the bearing mounting area. This will simulate actual part function.

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FULL FULL INDI INDICA CATOR TOR MOVE MOVEME MENT NT — CIR CIRCU CULA LAR R RUN RUNOU OUT T AND AND TOTA TOTAL L RUN RUNOU OUT T

Runout is the full indicator movement (FIM) of a measuring device as the part is rotated rotated on its datum datum axis. Reading direction is taken taken normal (90º) to the toleranced surface. NOTE: FIM is the term used internationally internationally and should replace total total indicator reading (TIR) which is a United States term.

Circular runout is the FIM on a single location on the surface over one revolution.

Total runout is the FIM as the indicator traverses the total surface while maintaining the normal attitude, measuring one continuous tolerance zone. NOTE: Total runout also controls controls straightness of the feature within within the continuous tolerance zone.

6.5

APPLICATION TION OF CIRCULAR R RU UNOUT

Circular runout can be applied to a cone, a perpendicular plane surface, or a radiused groove in addition addition to a cylinder. In the illustration shown, each circular line element taken normal (90º) to the indicated surfaces must lie within 0.05 FIM when the part is rotated 360º on datum axis A–B.

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PROCEDURE / DRAFTING 6.6

FNHA-3-B-072.00

APPLICATION TION OF TOTA TOTAL L RUNOUT

Where total runout is applied to a cylindrical surface, the entire surface must lie within the specified total runout tolerance when rotated rotated on the datum axis. In the illustration shown, the entire surface must lie li e within 0.1 FIM while the part rotates on datum axis A and the indicator transverses the total surface and maintains normal attitude. attitude. This same procedure applies to conical surfaces and again the indicator transverses the total surface maintaining normal (90º) attitude to it.

Total runout applied to datum surfaces Where datum features are required by function to be included in the runout control, runout tolerances must be specified for these features. This will indicate any misalignment of the individual individual datum feature axes axes to each other. other. In the illustration illustration shown, the entire surface of each datum feature must lie within 0.02 FIM while the part rotates on datum axis A–B.

Total runout can also be applied to a portion of a surface s urface as shown to the right.

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APPL APPLIC ICAT ATIO ION N OF TOTA TOTAL L RU RUNO NOUT UT (con (conti tinu nued ed))

Plane surfaces perpendicular to a datum axis

Where total runout is applied to a plane surface that is perpendicular to a datum axis, the entire surface must lie within the specified total runout tolerance when rotated rotated on the datum axis. In the illustration shown, the entire surface must lie li e within 0.1 FIM while the part rotates on datum axis A and the indicator transverses the total surface and maintains normal attitude. NOTE: The concavity and and convexity of this surface is also controlled controlled within the specified total runout tolerance.

6.7 6.7

APPL APPLIC ICAT ATIO ION N OF OF RUNO RUNOUT UT CON CONTR TROL OL TO MUL MULTI TIPL PLE E DAT DATUM UMS S

A multiple datum for runout control may be used as follows:

In some situations due to part function it is important to control runout to a plane surface as well as to an axis. This is illustrated by the example to the the right.

In other situations, the cylindrical surface referenced as a datum may be of insufficient length to properly determine a datum axis so a plane surface is used in conjunction to it to to properly orient the part. part. This is illustrated by the example to the right.

NAME

PART NUMBER

STD GEO DIM & TOL

PROCEDURE / DRAFTING 6.8

FNHA-3-B-072.00

EXAM XAMPLES OF OF RU RUNOUT TOL TOLE ERANCES

NAME

PART NUMBER

STD GEO DIM & TOL


FNHA-3-B-072.00

TOLERANCES OF LOCATION 7. TOLERAN TOLERANCES CES OF LOCA LOCATION TION.. This sectio section n defi defines nes met method hods s of of tole toleran rancin cing g to to contr control ol the locati location on of a feat feature ure of size in relationship to another feature. The tolerances of location are position, concentricity, and symmetry; symmetry; however the only one used by New Holland will be position. 7.1 POSITI POSITION ON TOLERA TOLERANCE NCE.. A positi position on tole toleran rance ce define defines s a zone zone within within w whic hich h the cent center, er, axis axis,, or cente centerpl rplane ane of of a feature of size is permitted to vary from its theoretically exact position. Position tolerancing provides a method of location to ensure assemble-ability and interchangeability at maximum tolerance. 7.1.1 7.1 .1

Conven Con ventio tions ns rela related ted to positi positiona onall contr control ol

Exact relationship

Basic dimensions are used to establish the exact location of the tolerance zone of a feature of size to its datum or to another position toleranced feature of size.

Features shown at 90º have an implied exact 90º relationship between their tolerance zones when a position tolerance is specified.

Material condition All position tolerance will be applied at MMC for the designated features of size and their related datums datums unless otherwise specified. A note is included in the title block of each drawing stating this. The symbol will not be used M with the feature control frame for position tolerance since through use of the note it is understood to apply. Tolerance zone Where the symbol ∅ precedes the tolerance value, the tolerance zone is cylindrical in shape. Where no ∅ symbol is specified, the tolerance value represents the distance between two parallel planes.

NAME

PART NUMBER

STD GEO DIM & TOL


FNHA-3-B-072.00

Bene Benefi fitt of of posi positi tion on tole tolera ranc ncin ing g

Coordinate system versus position system

The top figure shows a part dimensioned by the coordinate system. Under this system the tolerance tolerance zone within within which the axis of the hole must lie is i s a square (or rectangular) zone equivalent to the specified dimensional tolerance. This tolerance zone must be small enough so that hardware will always fit between it and its mating part when both are at MMC. This tolerance zone is constant and does does not increase as the holes depart from MMC, so the potential for increasing tolerance is not used.

The bottom figure shows the same part dimensioned by the position system. Under this system system the tolerance zone zone within which the axis of the hole must lie is a cylindrical zone specified by a position tolerance. tolerance. The diameter of the tolerance zone can be equivalent to the across corner dimension of the coordinate tolerance, thus providing 57% additional tolerance at MMC in the four segments of the diameter as shown. Additionally, as the holes depart depart from MMC toward their LMC, the diameter of the tolerance zone increases accordingly. accordingly. This provides “BONUS TOLERANCE” without affecting fit up to mating parts.

NAME

PART NUMBER

STD GEO DIM & TOL


FNHA-3-B-072.00

Benefi Benefitt of of posit position ion tolera toleranci ncing ng (con (contin tinued ued))

Further illustration

The top figure further illustrates the allowable location of the holes in the part shown on the previous page.

The bottom figures show a gage that would check the hole location to the allowable tolerance. tolerance. Functional gaging techniques are fundamentally based on the MMC position concept; however gages are not mandatory to fulfill MMC position inspection.

NAME

PART NUMBER

STD GEO DIM & TOL


FNHA-3-B-072.00

Appl Applic icat atio ion n of pos posit itio ion n tole tolera ranc nce e

Series of holes Where a series of holes are located by a position tolerance, the axis of each hole when at MMC must lie within a cylindrical tolerance zone equivalent equivalent to the specified tolerance diameter. Each cylindrical tolerance zone must be centered on the perfect center distance between holes. As the holes depart in size from MMC toward their LMC, the diameter of the cylindrical tolerance zone will increase accordingly.

Additionally A series of holes that are position toleranced to each other can also be position toleranced to datum features by the use of a composite feature control frame. In such situations, the centers of those those zones in relationship to each other must fall within the cylindrical tolerance zones established in relationship to the referenced datums. The centers of the holes must fall simultaneously within both tolerance zones.

NAME

PART NUMBER

STD GEO DIM & TOL


FNHA-3-B-072.00

Applic Applicati ation on o off posit position ion tolera tolerance nce (conti (continue nued) d)

Series of holes (continued) Where the same tolerance is required between holes in a series and between those holes and other features, a single feature control frame can be used with the the related features referenced as as datums. In such situations, the axis of each hole at MMC must lie within a cylindrical tolerance zone equivalent to the specified position tolerance. tolerance. Each cylindrical tolerance zone must be centered centered on its perfect location in relationship to to the datum features. As the holes depart in size from MMC toward their LMC, the diameter of the cylindrical tolerance zone will increase accordingly.

NAME

PART NUMBER

STD GEO DIM & TOL


FNHA-3-B-072.00


Bolt circle — punched holes

It is a common practice for a number of holes to be located on a bolt circle that shares a common axis with a related cylindrical feature feature of size. In such situations, a position tolerance will be assigned to the holes on the bolt circle with the related cylindrical feature referenced as a datum. datum. In the example to the right, right, the axis of each hole hole at MMC must lie within the specified cylindrical tolerance zone which is centered on perfect dimensions in respect to datum plane A and the MMC of datum D. As the holes depart in size from MMC toward their LMC, the diameter of the cylindrical tolerance zone will increase accordingly. accordingly. Also as the diameter of datum feature D departs from MMC toward LMC, the allowable position will be affected.

NAME

PART NUMBER

STD GEO DIM & TOL


FNHA-3-B-072.00


Bolt circle — punched holes (continued)

The figures to the right show a gage that would check the hole locations of the part on the previous page to the referenced datums by the allowable tolerance.

Additionally *NOTE: (See preceding page also.) If the angular rotation of the hole pattern to other part features is not critical, it will be controlled by the implied 90º angle with the angular tolerance specified in the title block applied. If a more restrictive tolerance to control rotation to a part feature is required, that feature should also be referenced as a datum. See the example example to the right.

The figures to the right show a gage that would check the hole locations in the above part to its position tolerance.

NAME

PART NUMBER

STD GEO DIM & TOL


FNHA-3-B-072.00


Bolt circle referenced to a machined datum

Where holes on a bolt circle are position toleranced to a machined feature of size, the virtual condition of that feature of size must be considered. Shown to the right is an example of such a part and shown below is an example of a gage to check the part.

NAME

PART NUMBER

STD GEO DIM & TOL


FNHA-3-B-072.00


Projected tolerance zone Where the variation in perpendicularity of a threaded hole or dowel pin hole could cause interference between the screw or pin and the mating part, a projected projected tolerance zone may be specified. Where a projected tolerance zone is specified, the projected axis of the hole must lie within the specified cylindrical tolerance zone for the height above the part surface that is specified with the feature control control frame. The leader for the callout must be directed to the the side of the part that the projected zone must be. A projected tolerance zone zone should be considered when the mating part part is of sufficient thickness that an assembly problem could exist.

NAME

PART NUMBER

STD GEO DIM & TOL


FNHA-3-B-072.00


Coaxial features

Where a cylindrical feature is given a position tolerance to a cylindrical datum that shares the same axis, the axis of that feature at MMC must lie within the specified cylindrical tolerance tolerance zone. That cylindrical tolerance tolerance zone is centered on the axis of the datum feature at MMC.

As the toleranced feature or datum feature depart from MMC toward their LMC, the cylindrical tolerance zone will increase accordingly. accordingly. Shown below is a gage that would check this part according to the specified tolerance and the illustration of the worst allowable misalignment condition of the axis of the two bores.

NAME

PART NUMBER

STD GEO DIM & TOL


FNHA-3-B-072.00


Coaxial features

Where cylindrical features of the same diameter are shown on a common axis with a position tolerance to each other, a pin equal to the MMC of the features minus the specified ∅ tolerance zone must pass through all features simultaneously. Additionally, each feature must lie within the specified dimensional tolerance.

Additionally The position tolerance shown above controls only the size of pin that the holes holes must accept. It does not control the relationship of the axis of the holes together to the rest of the part any closer than the dimension tolerances. If a tighter tighter relationship to another feature is required, an orientation tolerance can be added and referenced to the related feature. In the example to to the right, the axis of both holes together must lie within a 1 mm tolerance zone to datums A and B.

NAME

PART NUMBER

STD GEO DIM & TOL


FNHA-3-B-072.00


Coaxial features (continued)

The same method can be used to position tolerance cylindrical features of unequal diameter that are shown on a common axis. In this situation however, the note “2 holes together” must be included with the feature f eature control frame. A step pin equal to the MMC MMC of each feature minus the specified ∅ tolerance zone must pass through all features simultaneously. Additionally, each feature must lie within the specified dimension tolerance.

Additionally As on the previous page, the position tolerance shown above controls only the size of pin that the holes must accept. It does not control the relationship of the axis of the holes together to the rest of the part any closer than the dimension tolerances. If a tighter tighter relationship to another feature or features is required, an orientation tolerance can be added to the axis and referenced to the related feature or features. In the example to the right, the axis of both holes together must lie within a ∅ 1 mm tolerance zone to datums A and B.

NAME

PART NUMBER

STD GEO DIM & TOL


FNHA-3-B-072.00


Bidirectional position tolerancing

Where the allowable tolerance between features is different in one direction than the allowable tolerance in its perpendicular direction, position tolerances can be specified bidirectionally. bidirectionally. As illustrated in the the figures to the right, the center of the slots must lie within a rectangular tolerance zone equivalent to the specified position tolerances when the holes are at MMC. This tolerance zone is centered on the the centerplanes of the datum features. As the slots depart from MMC toward their LMC, the tolerance zone will increase accordingly.

NAME

PART NUMBER

STD GEO DIM & TOL


FNHA-3-B-072.00


Holes in shafts Where a hole in a shaft is position toleranced to the O.D. of the shaft, the axis of the hole at MMC must lie within a cylindrical tolerance zone equivalent equivalent to the diameter of the specified position tolerance. The cylindrical tolerance zone must be centered on and perpendicular to to the axis of the shaft. As the diameter of the hole departs from MMC MMC toward its LMC, the diameter of the tolerance zone will increase accordingly. accordingly. Additionally, the axis of the hole must lie totally within the locating dimension tolerance.

Keyways, Keyways, tabs, spline teeth, sprocket teeth, etc. Where a tab, keyway, sprocket, or spline tooth, etc., are position toleranced to other part features, the centerplane of the toleranced feature at MMC must lie between two parallel planes separated by the the position tolerance. The tolerance zone created by the two parallel planes must be centered on the perfect location to the MMC of the datum features. Another way of expressing this requirement is to define the boundary within which the part must lie (as shown below).

NAME

PART NUMBER

STD GEO DIM & TOL


FNHA-3-B-072.00

7.1.4 7.1.4 Calculatio Calculation n of position position tolerance tolerances. s. This sectio section n defines defines the method method of calculating calculating the maximum position position tolerances that can be applied. 7.1.4.1 7.1. 4.1

Mating Mating parts parts with floatin floating g fasteners fasteners (clearan (clearance ce hole in in each part) part)

7.1.4.2 7.1. 4.2

Mating Mating parts with with fixed fasteners fasteners (clearan (clearance ce hole in one, other other pinned pinned or drilled and tapped) tapped)

Since the fastener is fixed in one part and only one part has clearance holes, the ∅0.8 is the total allowable sum of the tolerance zones applied to both parts. The total allowable tolerance need not be divided evenly between between the mating parts. It should be divided in the most useful amounts for manufacturing. manufacturing. The position tolerance for these mating parts parts could be ∅0.4 and ∅0.4, ∅0.5 and ∅0.3, ∅0.6 and ∅0.2, etc.

NAME

PART NUMBER

STD GEO DIM & TOL

PROCEDURE / DRAFTING 7.1.4.3 7.1. 4.3

FNHA-3-B-072.00

Two or more more fixed diameters diameters aligning aligning for a shaft shaft

NAME

PART NUMBER

STD GEO DIM & TOL


FNHA-3-B-072.00

8. FREE FREE STATE STATE VARIAT VARIATION ION.. Free Free state state variat variation ion is a term term used used to desc describ ribe e dist distort ortion ion of a part part after after remova removall of forces applied during manufacture. This distortion is principally due to the weight and flexibility of the part and the release of internal stresses resulting from fabrication. A part of this kind is referred to as a non-rigid part. part. 8.1 8.1

SPEC SPECIF IFYI YING NG CIR CIRCU CULA LARI RITY TY IN IN A FRE FREE E STATE STATE WITH AVER AVERAGE AGE DIAM DIAMET ETER ER

In some cases, it may be required that that the part meet its tolerance requirements requirements while in the free state. In such situations, the maximum allowable free state variation should be specified with an appropriate feature control frame. Where form control such as circularity is specified for a circular or cylindrical feature, the pertinent diameter is qualified with the abbreviation AVG. An average diameter is the average average of several diametrical measurements (usually not less than four) across a circular or cylindrical feature. Illustrations (a) and (b) (simplified by showing only two measurements) measurements) give the permissible diameters in the free state for two extreme conditions of maximum average diameter and minimum average diameter, respectively.

NAME

PART NUMBER

STD GEO DIM & TOL


FNHA-3-B-072.00

SPEC SPECIF IFYI YING NG RE REST STRA RAIN INT T FOR FOR NONNON-RI RIGI GID D PAR PARTS TS

In some cases, it i t may be necessary to simulate the mating part interface in order to verify individual or related feature tolerance. This is accomplished by restraining the appropriate appropriate features such as the datum features features shown in the illustration below. In this illustration, illustration, the runout of the B. Additionally in the part’s free state, the

1391 ∅1390

∅1390

must be checked when the part is restrained to datums A and

must be round within within a 2.5 tolerance tolerance zone. The

1391

∅1390

AVG would be

checked as described in paragraph 8.1.

NAME

PART NUMBER

STD GEO DIM & TOL

GD&T

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