Geometric Dimensioning Tolerancing 102

REV. A

Geometric

Dimensioning &

Tolerancing

ASME Y14.5M, 1994

Geometric D imens ioning & To le ranc ing ASME Y14.5M-1994 P a ge 2 of 1 02

Table of Contents

1. Gener

al

Rules

...

...

...

3

2. Geometric

Characteristic

s

and

Symbols

...

8

3. Datum

...

...

...

19

4. Form

Tolerance

...

...

...

46

5. Orientation

Tolerance

...

...

54

6. Profile

Tolerance

...

...

...

65

7. Runout

Tolerance

...

...

75

8. Location

Tolerance

...

...

83

Geometric D imens ioning & To le ranc ing ASME Y14.5M-1994 Page 3 of 102 1. General Rules 1.1 . Rule 1 – Limits of Si ze 1 .1 .1 . Individual Fe ature of Size Where on ly a tole ra n ce of size is specif ie d , the limits o f size of an ind ivid ual fe atu re prescri be the ex te nt to which v ari ati ons i n it s g eometri c form and size are all o w ed. 1. 1. 2. V a ri at io n s o f S iz e T h e actua l size of a n indiv idual fea ture at a ny cros s-se cti on shal l be wit hin the spe cified t o lerance of size. 1. 1. 3. V a ri at io n s o f F o rm ( E n ve lo p e P ri n ci p le ) a ) T h e s urfa ce or s urfaces of a fe at ure s hall not ex tend be yo nd a boundary (env elope) of p erf ect fo rm a t Maximum Ma te ria l Con di tion (MMC). Th is b oundary is th e tru e geom

etric form repre

sen ted b y the dra w ing. No va riati on in form is p erm itt e d if t h e fe ature is produced at its MMC li mit of size . n 20 +0 .1 -0 .1 n 20. 1 (L M C ) n 20 +0 .1 -0. 1 n 20.1 (MMC) n 19 .9(L M C ) n 19.9 (L MC ) n 19. 9(M MC ) n 19.9 (M MC ) n 20 .1 ( M MC ) n 20.1 (L M C ) BO UN DA R Y OF P E R FECT FO RM A T MMC E X T E RN A L FE A T URE IN T E R N A L FE A T URE b ) Where

the actual loc

a l size of a fe at ure has departed from MM C toward Least Material Conditi on (LMC), a v a ria tion in fo rm is a llowed eq ual to the a m ou nt o f su ch departure. Geometric D imens ioning & To le ranc ing ASME Y14.5M-1994 P a ge 4 of 1 02 c) T h ere is no require m en t for a boundary of perf e ct f o rm as LM C. 1. 1. 4. R e la ti o n sh ip b e tw ee n In d ivi d u al F e at u res Th e limits of size do not control t h e ori en tati on or loc ation re la tion sh ip be tw een indiv idua l f eatures. Fe at ure s shown perpendic u la r, coa xi a l, o r sym met ric a l to eac h othe r must b e controll ed for l ocati on or orienta tion to a voi d inc o m plete dr aw ing requ irements . 1 .2 . Rule 2 – A p plicabili ty of F ea ture Size Appl ic ability of ma te rial condi tion mod ifier (RFS, M M C, L M C) i s li mited to featu res subject t o v aria tion s in siz e. Th ey may be datum features or othe r fea tu res whos e a xes or ce n tre pl ane s are controlled by geome tric tole ran ces. FOR AL L Applicabl e Geo m etric Toleranc es: RFS ap pli es wi ll re sp e ct to the ind iv idual to le rance , datum refe rence, o r both , wh ere NO MO DIFYING SYMBOL is speci fied . . “ASME Y14 .5 -19 94” j n 0 .5 A j n 0 .5 m Am j n 0 .5 m A 1. 3. R u le 3 All other c on trols is impl ied Regard less o f Fea tu re Size (RFS). 1 .4 . P itch Rule a ) Each tol eran ce o f ori entation or positi on and da tum re feren ce specified for a screw th read appl ies to the ax is of th e thread de riv ed from the p itc h cylinder. j n 0 .5 A A M AJ O R n M AJ O R n LM C S IZ E

Geometric D imens ioning & To le ranc ing ASME Y14.5M-1994 Page 5 of 102 b ) Each toleran ce of orien tation o r po sition and da tum r ef erenc e specified fo r featu res othe r tha n screw threads, such as gears and spl ine s, must des ign at e t h e specific fe atu re to wh ic h ea ch appl ies. j n 0 .5 A A P D n P D n Int ernal T hread (t apping) Ext ernal T hread (scr ew ) 1 .5 . Virtual Conditio n A const ant boundary genera te d b y the collecti ve effects o f a size fea tu re’s spe cifi ed MMC or LM C materi al conditi o n and t h e geome tr ic to le ran ce

for that material

conditi on. Th e v irt u al con diti on o f a fea tu re is the extreme bo undary of that feat u re whic h repre sen ts t h e ‘w o rst cas e ’ fo r, typ ic ally, such concerns as a clear anc e of fit possibi lity rela tive to a mating part o r situa tio n . PIN: VC = Si ze MMC + Tolerance VC = Size LM C – To le ra nc e HOLE: VC = Size M M C – Toleran ce VC = Size L M C + Toleran ce Geometric D imens ioning & To le ranc ing ASME Y14.5M-1994 P a ge 6 of 1 02 1. 6. E xe rc is e 1. A(n) __ ____________ ___ is a num erica l va lue expressed in appropria te uni ts of measure, in dicated o n a drawi ng and i n d ocum ents to d efine the size and /or geometric characterist ics and/or lo cations of features of a part. 2. _______ __________ is a g

eneral term applied

to a physica l portion of a part. 3. Define To lerance. _______ ____________ ____________ ____________ ____________ ____________ _____ _______ ___________ ____________ ____________ ____________ ____________ ______ _______ ____________ ____________ ____________ ____________ ____________ _____ _______ ____________ ____________ ____________ ____________ ____________ _____ 4. All Dimens ions shall

have a tolerance except

for dim ensions that are identified as: a) re fere nce. b) maximum. c ) mini mum. d) stock sizes. e)

all of the above.

5.

What are the limit of the dimension 25±0.4

? _________ __________ 6. What is the tolerance of the dim en sion in question 5 ?___ _________ 7. What is the nomi nal di me nsion of the dime nsion show n in question 5? _______ ____________ 8. Give an exam ple of a n equal bil ateral tolerance. _____ _______ ____ 9. Give an ex am ple of a n uneq ual bi lateral tol erance. ___ _________ __ 10. Give an exam ple of a unilateral toleranc e. _____________________ 11. Define Ma ximum Ma terial C ond ition (MM C ). _______ ____________ ____________ ____________ ____________ ____________ _____ _______ ____________ ____________ ____________ ____________ ____________ _____ 12. What is the

MMC of the feature shown b

elow? n 1 5 .0 0 + 0 .2 5

Geometric D imens ioning & To le ranc ing ASME Y14.5M-1994 Page 7 of 102 13. What is the

MMC of the feature shown b

elow? ____ ___ __________ n 1 5 .0 0 + 0 .2 5 14. Define Least M aterial Condition (L MC). _______ ____________ ____________ ____________ ____________ ____________ _____ _______ ____________ ____________ ____________ ____________ ____________ _____ _______ ____________ __ 15. What is the

LMC of the feature shown in question 12

? __

______

____

16. What is the

LMC of the feature shown in question 13

? __ ______ ___ 17. List the three ge neral

groups related to the

standard ANSI fits

be twee n mating parts. 1) ____ ____________ ____________ ____________ ____________ 2) ____ ____________ ____________ ____________ ____________ 3) ____ ____________ ____________ ____________ ____________ 18. Is the fit b etwe

en the two parts shown b

elow a clearan ce or a force fit? _______ ____________ ____________ ____________ ___________ 1 9 .4 3 1 9 .1 8 n 1 9 .7 6 1 9 .5 0 n Geometric D imens ioning & To le ranc ing ASME Y14.5M-1994 P a ge 8 of 1 02 2. Geometr ic Char ac ter istics and Sy mbols 2. 1. Sy mbo l Type of Tolerance Char ac ter istic

Symbol ASME Y14.5M-1994 Symbol ISO St raightness

u

u

Flatness

c

c

Circularity

e

e

For Individual Features

Fo rm Cy lindri city

g

g

Pro file of a Line

k

k

For Individual or Relat

ed Features Pro file Pro file of a Surfa ce

d

d

Ang ularity

a

a

Perpe ndi culari ty

b

b

Orient at io n Parallelism

f

f

Position

j

j

C on cent ric it y

r

r

Lo catio n Symmetry

i

i

Circular Runout

h

h

For R elated Features Ru no ut Total Runout

t

t

Geometric D imens ioning & To le ranc ing ASME Y14.5M-1994 Page 9 of 102 Sym b ol for: ASME Y14.5M ISO At Maximum Mat erial Condi tio n

m

m

At Leas t Material Condi tio n

l

l

Regardless of Feat ure S ize N O N E N O N E Proje cte d Tole rance Zo ne

p

p

Diameter n n Spherical Diameter S n S n Squa re o o Number of Places X X Counterbore v v Countersi nk w w Dep th

x

x

All Ro un d Bet w een N O N E Arc Length

10

10

Radi us R R Spherical Radi u s S R S R Contro lled Radi us C R N O N E Conical Taper y y Slo pe z z Tang en t Plane T T Free St at e F F Statist ical T olerance

ST

N O N E Geometric D imens ioning & To le ranc ing ASME Y14.5M-1994 Pa ge 10 of 102 Radi us, Contro lled Radi us There are tw o types o f ra di i to le ranc e th at can be appl ied , the radi us and con tro lled radiu s. The radius (R) tolera nce is fo r general applic ati o ns. The cont rol led radi u s (CR) is u sed when it is necessar y to p lace fu rt her re st rict ion s on the

shape of the radiu

s, a s in hi gh stress applica tion s. 12 .7 12 .3 CR 12.7 12.3 R Min Ra dius 12. 3 Min Ra dius 12. 3 Max Radius 12.7 Max R adi us 12.7 Part cont our must fal l wi thi n zone de fin ed by Ma x and

Min radius tolera

nce P art cont our must be a fair cur ve with no reve rsa ls. All rad ii p oints must be 1 2.3 min to 12.7 max . Radi us , R Contro ll ed Radi us , CR On drawing Mea ning On drawing Mean ing

Geometric D imens ioning & To le ranc ing ASME Y14.5M-1994 Page 11 of 10 2 St at istical Tolerance Oft e n, t o lerances are ca lc u lated on a n arit h m etic basis. Toleran ces are assigned to indiv idual feature s on a com ponent by div iding the tota l assembly toleranc e by the num ber o f componen ts a nd a ssi gning a po rti on of this t o leranc e t o e ac h component. Whe n tolerances are st a cked up in th is ma nner, the to le rance may beco me very re st rictiv e or tight. Statist ical toleran ci ng is th e as signmen t of to le ranc e s to relat ed comp one nts of an a ss emb ly on the ba si s of sound st atistics. An e xampl e is, th e ass embly toleranc e is equa l to the square roo t o f the su m of th e squares o f the indiv idual t o le ran ce. Statist ical Toleranc e may be app lied to fea tu res to in crea se toleran ces a nd reduce manu fa ct uring c ost. To en su re compatibi lity, the larger tol eran ce i dentified by the statist ical tol eran ce s ymbol may only be used w h ere appropriat

e statistical process cont

ro l wi ll b e used. A n

ote such as the

one s h own below shall be pl a ced on the dr awing . 16.07 15.93 n 20 .2 19 .8 n 16.1 15.9 n 0.2 A B 0.5 A B NOTE: FEATUR ES I N DENTI FI E D AS S T ATI S TI C A L TOL E R ANC E S HAL L BE P R ODUC ED W ITH STA T IS TI CA L PRO C ESS CO N T RO L S , OR TO THE MORE RE STRI CTI V E ARI T HMET IC LIM IT S Geometric D imens ioning & To le ranc ing ASME Y14.5M-1994 Pa ge 12 of 102 Free Sta te Unl e ss othe rwis e s

pecified, all dim

en si oni ng and toleranci ng appli es in a free stat e conditi on with no rest ra in t. So me pa rt s, such a s sheet metal, thin metal, plastics an d rubbe r are non-ri g id in na ture. It may be necessary to spe cify des ign requirements on the part in a natural or free st a te a s well a s in a re strained conditi on. T h e restraint o r force o n the non righi9d part s is u sually appli ed in su ch a manner to res emb le or appro xim a te t he fun ction al or m ating requ iremen ts. A no te o r specificati on on th e dra w ing shoul d e xplai n h ow the pa rt is rest ra in ed an d th e force required to faci lit a te the restraint. A sample note can be found on th e drawing below. The free

state symbol means t

h at d imens ions and t olerances that h av

e the free state

symbol appli ed are checked in t he free state a nd not in the re strai ned conditi on. 3 F 2 S URF 2 S URF n 4X 5.4 - 5.6 0. 2 M n A B A 65 32 25 36.8 5.6 UNLESS OTHER W ISE S P EC IF

IED, ALL UNTOLERANCED

DI M E NSI ONS AR E B A SI C. PAR T I S TO BE R E STR A IN ED ON DATUM A W ITH 4 5 M SC R E W S

Geometric D imens ioning & To le ranc ing ASME Y14.5M-1994 Page 13 of 10 2

ASME Y14 Series

ISO Standards

Y14.2 – Lines & Lettering

3098

Y14.3 – Sections & Views

128

Y14.5 – Dimensioning &

Toler

ancing

129, 406, 1101, 1660,

R1661, 2692, 5455,

5458, 5459, 7083,

8015, 10579; (also

14660-1 & 14660-2)

Y14.6 – Screw Thread

Representation

6410-1, 6410-2, 6410-3

Y14.8 – Casting &

Forgings

Y14.36 – Surface Texture

Symbols

1302

Geometric D imens ioning & To le ranc ing ASME Y14.5M-1994 Pa ge 14 of 102

Basic Dimension

(theoretically

exact dimension in ISO

)

65

R

e

ference D

imension (auxiliary

dimension

in

ISO)

(68)

A

D

a

tu

m F

e

at

ur

e

A

D

imension Or

igin

Feature Control Frame

C

B

A

Ø 0

.5

M

D

a

tum T

a

rg

et A

rea

Ø8

A1

A1

Ø2

0

D

a

tum Ta

rg

et P

oint

A1

Da

tum Ta

rg

et Line

A1

Geometric D imens ioning & To le ranc ing ASME Y14.5M-1994 Page 15 of 10 2 Geometric Char a ctieristic Overview Appl icabili ty of D atum Modifi ers N/A N/A N/A N/A N/A Yes if size feat ures Yes if size feat ures Yes if size feat ures No No Yes if size feat ures Yes if size feat ures Yes if size feat ures No No Applicability of Featur e Modifiers No Yes No No No No No Yes No No Yes if size feat ures Yes if size feat ures Yes if size feat ures No No Surface X X X X X X O X X X X X Controls Axis or Med ian Plan e X X N N X X X 2D o r 3D 2D 3D 3D 2D 3D 2D 3D 3D 3D 3D 3D Q 3D Q 3D Q 2D 3D Sym bo l u u c e g k d j r i a b f h t Characteristi c Straightne ss Line Element Straightne ss Axis or M edi an P lan e Flatness Circular ity Cylindri city Pro file of a Line Pro file of a Sur fac e Posi tion Concen tricity Symmetry Angu larity Perpendicu lar ity Para llel ism Circ ula r Ru nout Total Run out Type of Tolera nce Form Profile Loca tio n Orientation Runout P Datums Datums NOT allowed Datums Required M Datums Requied M Ther e are spe cial ca se where po sition and profile may not req uire datums N These char acter ist ics contr ol opp osing median points O Can also cont rol surface bou ndary P Can control form, orie nta tion an d loca tion Q These ch arac terist ics can b e made 2D by writing “LINE ELE MENTS” un der the fea tu re control fram e Geometric D imens ioning & To le ranc ing ASME Y14.5M-1994 Pa ge 16 of 102 2. 2 E x er ci se A di m ensioning and tolerancing template is

recommended for drawing proper

sy

m

bols on this

test and on future tests.

1.

L

ist the fiv

e basic types of geom

etri c di me ns ionin g an d tole ran cin g symbols. a) ________ ____________ ____________ ____________ ____________ ____ b) ________ ____________ ____________ ____________ ____________ ____ c) ________ ____________ ____________ ____________ ____________ ____ d) ________ ____________ ____________ ____________ ____________ ____ e) ________ ____________ ____________ ____________ ____________ ____ 2. Name the five types of g eometric charac teristic sy m bols. a) ________ ____________ ____________ ____________ ____________ ____ b) ________ ____________ ____________ ____________ ____________ ____ c) ________ ____________ ____________ ____________ ____________ ____ d) ________ ____________ ____________ ____________ ____________ ____ e) ________ ____________ ____________ ____________ ____________ ____ 3.

Name each of the follo

wing ge om etric chara cteristic sym bols.

u

___________________

r

____

_______________

c

___________________

i

____

_______________

e

___________________

f

____

_______________

g

___________________

a

____

_______________

k

___________________

b

____

_______________

d

___________________

h

____

_______________

j

___________________

t

____

_______________

Geometric D imens ioning & To le ranc ing ASME Y14.5M-1994 Page 17 of 10 2 4. A ny letter of

the alphabet can be used to id

entify a datu m except for __ __, ____, or ____. 5. When may datum feature sy mb ols be repeated on a dra w ing? ___________ ____________ ____________ ____________ ____________ ____________ ___ ___________ ____________ ____________ ____________ ___ 6. What inform atio n is p

laced in the lowe

r half of

the datum targ

et symb ol? ___________ ____________ ____________ ____________ ____________ ____________ ___ ___________ ____________ ____________ ____________ ___ 7. What inform atio n is p laced in

the top half of

the datum ta rge t symbol? ___________ ____________ ____________ ____________ ____________ ____________ ___ ___________ ____________ ____________ ____________ ____________ ____________ ___ ___________ ____________ ____________ ___ 8. La bel the pa rts of the following

feature control frame.

(A)

(B)

(C)

(D)

(E)

(F)

(G)

j

n

0

.0

5

m

A

B

m

C

Geometric D imens ioning & To le ranc ing ASME Y14.5M-1994 Pa ge 18 of 102 9. C om pletely

define the term “basic dimension”.

___________ ____________ ____________ ____________ ____________ ____________ ___ ___________ ____________ ____________ ____________ ____________ ____________ ___ ___________ ____________ ____________ ____________ ____________ ____________ ___ ___________ ____________ ____________ ____________ ____________ ____________ ___ ___________ ____________ ____________ ____________ ____________ ____________ ___

10. How are basic dimensions show

n on a drawing ? ___________ ____________ ____________ ____________ ____________ ____________ ___ ___________ ____________ ____________ ____________ ____________ ____________ ___ ___________ ____________ ____________ ___ 11. Name the following symbols.

n

___________________

r

____

_______________

R

___________________

o

____

_______________

S

R

___________________

(6

8

)

____

_______________

C

R

___________________

x

____

_______________

S

n

___________________

____

_______________

X

___________________

y

____

_______________

v

___________________

z

____

_______________

w

___________________

ST

____

_______________

___________________

65

____

_______________

Geometric D imens ioning & To le ranc ing ASME Y14.5M-1994 Page 19 of 10 2 3. Datum 3.1. Da tu m Co n cep ts A da tu m is a theo reti cal ly exact p oi n t, ax is, or pl ane de riv e d from the true geom e tric coun te rpa rt of a sp ec ified da tu m fea ture. A datum is t he ori gin from whic h the l o ca tion o f geome tr ic chara ct erist ics o f fe ature s o f a part are establishe d. Datu ms a re e stablis hed by sp eci fied featu res or surface s. Where o rientati o n or po si tion rel a tion sh ips a re s pe ci fied f ro m a datum, t he feature s in vo lv e d are lo ca ted wit h res p ect to this dat um a nd not with re sp e ct to one anothe r. Ev ery fe ature on a part can be consi de red a possi ble d atum. That is, ev e ry featu re shown on a drawi ng depicts a theore tically e xact geome tr ic shape a s s pe cified by the design requi re men ts. Howev e r, a fe ature nor mally has n o p ractic a l mean in g as a datum unl ess it is actually us ed for so me fu ncti onal relati ons hip be tw een fea tu res. Th us a da tu m appe aring on an eng ineering drawing can be con si dered to h av e a d ual nature : it is (1) a “const ru ction” datum, whic h is geometrically ex act re presentation of any pa rt fea ture, and (2) a “rela tionshi p ” dat u m , whic h is an y fea ture u sed as a basis fo r a fu nctional re lationship with o ther feature s on the part. Sin ce th e d at um con cep t is u sed to establish rel a tion sh ips, the “re lationshi p ” datum is th e only typ e u sed on en gi nee rin g dr aw in gs . By th e abov e d efi n iti on, a da tu m on an engi neeri ng draw ing is always a ss umed to be “perf ect ”. Howev er , sin ce pe rf e ct p arts cannot be p rodu ced , a datum on a physic ally p roduced part is ass u med to ex ist in the contact o

f the actual feature

surface with p rec ise manufactu ring or i n spection equipment such as ma ch ine table s, surf a ce pl at es, gage pi ns, e tc. The se a re call ed d at um simulators whic h cr eate simul ated da tum p lanes, a xes, e tc. , a nd, whi le not p erfectly t ru e, a re u sual ly of such high qu al ity that th ey adequately simulate true re fe ren ces. Th is cont a ct o f the a ct ual fea ture with p rec ise equ ipm ent is als o a ss umed to si mul a te functional c o

ntact with a mating

par t su rfac e . Da tum fea ture : The actual surface of th e pa rt . Si mula ted datum : The pl ane establ is he d by the inspe ction equ ipment suc h a s a su rfac e pl at e o r in spection table. Da tum pl an e : The t h eo retic ally e xact pl ane e st ablis hed b y t h e true geome tric coun te rp a rt o f the datu m feat ur e. Geometric D imens ioning & To le ranc ing ASME Y14.5M-1994 Pa ge 20 of 102 3. 2. E s tabl is hi ng Dat u m Pl an es Dat um feature s are se le ct ed bas e d on t heir im po rt ance to the des ign of th e part. Ge nerally t h ree datum f e ature s are sele ct ed tha t a re pe rpe ndi cular to e ac h o ther. Th es e th ree datums are c all ed t he datum referenc e fr ame. The datu ms that ma ke up th e dat u m re feren ce frame a re ref e rred to as the pri m ary dat u m, se condary datum, and te rt iary datum. As their nam es imply, the primary datum is t he mo st i m port an t, fo llow e d by the o

ther two in ord

er of importan ce . 90 O 90 O 90 O 90 O M E A S URING DIRECTI O N FOR RELA TED DIMENSI ONS ESTA B LIS H TERTIA RY DA TUM PLA N E (MIN 1 POINT) CONTA C T WITH D A TU M SURFA C E C ESTA B LISH SE C O NDA RY DA TUM PLA N E (M IN 2 POI N T) CON T A C T W ITH DA TUM SURFA C E B ESTA B LI SH PRIMA R Y DA TUM PLA N E (M IN 3 POI N T) CON T A C T WI TH DA TUM SURFA C E A S im ulate d D at um S urface of m anufact ur ing or veri fication equip m ent Datu m Plane – the or et ical ly ex ac t Part Datu m Feature

Geometric D imens ioning & To le ranc ing ASME Y14.5M-1994 Page 21 of 10 2 3 .3 . Datum Identifi c ation Wh en a su rface is u sed to e st abli sh a datum p lane on a par t, t h e da

tum feature symbol

is pl a ced on the edge v iew of t h e surfac e or on an ex te nsi on l ine in the v iew where the su rfac e appears a s a li ne. A leader l ine may a ls o be used to conne ct the d atum fe ature sym bol to th e view in some appl icati ons. Datu m Axis 90 o 90 o 90 o Datum Axis D ire ct ion of me as ur em ents Dat u m P lan es or igin of meas u reme n t Datum Axis Dat u m Po in t Datum F eatu re S ymbol pl aced on edg e view of sur face or exte n si on li ne fr om edge view B C A A 10 C 30 50 B Sur face Datu m Featur e Sy mbo l must be of fset fr om dim en si o n li n e a rro w h ea d s D Ang led Sur face Geometric D imens ioning & To le ranc ing ASME Y14.5M-1994 Pa ge 22 of 102 3. 4. Da tu m Axi s A cylindrical ob je ct

may be a datum fea

tu re. Wh en the cylindrical da tum featu re is u sed , the centre a xis i s kn own as the d at um ax is. The re are two t heoretical plane s int ers e cti ng at 9 0º. Th e se planes are re pre sen ted by the ce ntreli n es of th e drawing. Wh ere the se pl anes in te rs ect is refe rred to a s the dat u m a xis. Th e da tu m ax is is th e o rig in for relat ed di mension s, whi le the X and Y plane s indic a te th e directi on of meas u rement. A da tum plane is ad ded to th e end of t h e ob je ct to estab lis h the da tum fra m e. _{Placement o} f the Dat um Fe ature Symbo l f o r a D a tu m Ax is Y T E R T IA RY DAT U M 30 30 30 30 Y X n 8 0 AX IS A B PA R T P R IM ARY DA TU M P L ANE X SE CO N DARY D A T U M DAT U M AX IS n 1 2 A A A n 1 2 D A B C Ø 0.4 M n 1 2 n 1 2 A

Geometric D imens ioning & To le ranc ing ASME Y14.5M-1994 Page 23 of 10 2 Simu la ted datum ax is T h e si mul ated da tum ax is is t h e ax is of a perfect cyli nd ric a l i n sp e ct ion d ev ice that con ta ct s the datum f eature s urf ace . For an ex ternal datum fea ture, the ins pecti o n

device is the smallest

(MMC) circumsc

ribed cylinder. The

in spec tion dev ice for a n int e rnal dat u m feature is th e la rgest (MMC) inscribed cy linder. SIMU LA TED D A TU M SM A LLEST C IRC UM SC RIB E D CYL INDE R DA TU M FEA T UR E (PA R T ) DA TU M A X IS DA T U M FEA T U R E SIM U L A T O R DA TU M FEA T UR E S IMULA TOR D A TU M FEA T UR E (P A R T) DA TU M A X IS S IMU LA TE D DA TU M L A RG E S T IN S C RI BE D CYL IND E R Si m ulated datum axis for an ex tern al datum feature Si m ulated datum axis for an internal d atu m feature Geometric D imens ioning & To le ranc ing ASME Y14.5M-1994 Pa ge 24 of 102 3 .5 . Co axial Da tu m F eatur es Co a xi a l me an s t w o or m or e cyli ndr ic al s ha pe s t hat sh ar e a co mm o n ax is. Coa xial datum fe ature s e xist when a si ngl e datum axis is e st ablis h ed by tw o datum features th at a re coa xial. When more tha n one da tu m fe at ure is u sed to est a blish a single datum, the da tu m ref e rence l e tte rs are sep ara ted by a d as h and plac ed in one co m partm en t of t h e feat ur e c ontr o l fra m e . T h es e d a tu m refere nce l e tte rs ar e of e q ua l im po rtance and may be pla ced in an y o rde r. 3 .6 . D atum A xis of Sc rew Threads, G e ars, a n d Spli ne s Wh en a

screw thread is used as

a datum ax is, th e da tu m ax is is e st ablis hed from t h e p itc h cylinder unless othe rw ise sp ecif ied . If another fea tu re of the screw th read is desired , then no te “ M AJOR DIA” or “MINOR DIA” is pla ced nex t to the d at um feature sy mbol. A spe

cific feature such

as the major di ameter should be i d entif ied when a ge ar or sp line is used as a datu m a xis. Whe n this

is done, the note

“MAJOR DIA” , “MINOR DIA”, o r “PITCH DIA” is p lac e d nex t to the datum fe at ure symbol a s ap propri a te . T h e u se of a s crew t h read, g ear, or spl ine s hould be av o ided for use as a datu m a xis unless ne ce ss a ry. A B 0.2 A -B t SI MU L A T E D PA IR OF COA X IA L CI RC UM S C RI BE D C Y L IN D E R S THE DR AWI N G THE MEANI NG

Geometric D imens ioning & To le ranc ing ASME Y14.5M-1994 Page 25 of 10 2 3. 7. Da tu m Cen ter P lan e Elements on a rectan

gular shaped symme

trica l p art or fea tu re may b e l o ca ted a nd d ime ns ioned i n rel a tion sh ip t o a datu m cent re pl

ane. The rep

res entati on an d related mean ing of datum center p lane symbols a re as sh own i n the fo llo w ing. 28 A 12 A

Da

tu

m

Center Plane

Dat

um

Center Plane

_{12 j}0 .2 m A B m C 12 B Geometric D imens ioning & To le ranc ing ASME Y14.5M-1994 Pa ge 26 of 102 Th e s imulated da tum centre plane is the centre pl ane of a perfect re ctang ular ins pecti on dev ice tha t conta ct s the d at um fe ature surface . For a n ext e rna l da tum fe ature t he datum c en tre pl ane is established b y two parall el plane s a t mini mum (MM C) separa tio n . For an internal da tum fea ture, the d at um centre plane is e stablis hed b y two paral lel p lanes a t ma xi mum (M M C ) separa tion . Datu m F eature Sim u lat or Datu m Cen ter Pla n e A Datum Fea tu re A T ru e ge om et ric co un te rpar t of dat u m fe at ur e A pa ra lle l pl ane s at m im im u m sep arta tio n (M M C ) Datum Fea tu re A Datum F eatu re Sim u lat or Datum Center Pl an e A T ru e g eo m etri c cou n terp art o f dat u m feat u re A p aralle l p lan es at ma xi mu m sep arta tio n (M M C )

Geometric D imens ioning & To le ranc ing ASME Y14.5M-1994 Page 27 of 10 2 3 .8 . Pa ttern of Holes as a D a tu m Th e c en te r of a pattern o f fea tures , such as the ho le s

in the part may be

spec ified as th e datum a xis when the da tu m f eature symbo l is plac ed under, and attached to, the mi dd le of th e fe at ur e co nt ro l f ra m e. I n th is a ppl ic at io n, th e d at um ax is is th e c en ter of th e holes as a g roup. n3 0 B 6 X n 8 .4 ₈.0 j n 0 .0 5 m A 6 X 6 0 o A Da tu m A xi s B Geometric D imens ioning & To le ranc ing ASME Y14.5M-1994 Pa ge 28 of 102 3. 9. Da tu m T arg et s In many situa tion s it is no t p oss ibl e to e st a bli sh an entire surf ace , or en tire sur fa ces, as datums. When th is h appen s, then datum targe ts may be used to e stablis h da tum p lanes. Th is procedu re is especially useful on pa rts

with surface or cont

o ur ir regularities, such as so me sheet m etal, sand cast, or forged parts tha t are su bject to bowi ng or warpage. This m e thod can als o be appli ed to weldm ents whe re he at may cause warpa ge. Dat um targets a re desi gna ted poin ts , lines, or s u rfac e areas that a re us ed to es ta bl is h t he da tu m r e fe re nc e fr am e. 45 20 N1 N1 N N L M N1 N1 45 N N n 1 2 N1 n 6 N1 45 45 20 20 Da tu m Tar g e t Poi n t Datum T a rg et Li ne Datum Tar g e t Ar ea Ar ea Shown Da tu m Tar g e t Ar ea Area N o t Sh own L L M M

Geometric D imens ioning & To le ranc ing ASME Y14.5M-1994 Page 29 of 10 2 Wh en datu m t arg et poin ts a re used on a dra w ing to iden tif y a d at um pl an e, t he datum pl ane is e st abl is he d by loc ating p ins at

the datum tan

gen t p oin ts. The loc ating p in s are rounded or pointed standa rd tooli ng ha rdware. 50 15 40 35 15 X3 X1 X2 50 15 X1, X2 X3 Datu m Pl an e X Loc at ing Pi n s Datum Feat u re T h e Pa rt The D rawi n g The Fi xtur e Setup Geometric D imens ioning & To le ranc ing ASME Y14.5M-1994 Pa ge 30 of 102 Areas of con ta ct ma y a lso b e used to e stablis h d at ums. The shape of the da tum ta rg et area is outli ned by phant om line s w ith section l

ines through the a

rea . Circ ular a rea s are d ime ns ioned with ba si c o r t o leranc e dimension s to located th e cen ter. Th e d iamet er o f t h e target area is prov ided in th e u pp er h alf o f t h e da tum targ et symbo l or with a le ader and do t pointi ng to th e uppe r ha lf. The lo ca ting pins fo r t a rge t areas are fla t e nd

tooling pins with the pin di

ame te r equ al to the specified siz e o f the target area. 20 X3 , n 12 Datum Plan e X Locat ing Pi n s Datum Fea tu re The Fi xtur e Setup 60 20 20 The Dr awi n g 40 50 n 12 X3 n 12 X2 n 12 X1 50 The P ar t X1 , n 12 60 X2 , n 12

Geometric D imens ioning & To le ranc ing ASME Y14.5M-1994 Page 31 of 10 2 When th e area is too s m all to acc ura te ly or c learly dis p la y on a drawing , a d at um ta rge t poi n t is u sed a t the center loc a tion.

The top half

of t h e da tu m targe t symbol identifie s t h e di ame te r of th e t a rget a rea. 20 X3, n 6 Datum Plan e X Loc at ing Pi n s Datum Feat u re The Fi xture Setup 60 20 20 The D rawi n g 40 50 n 6 X3 n 6 X2 n 6 X1 50 T h e P art X1, n 6 60 X2, n 6 Geometric D imens ioning & To le ranc ing ASME Y14.5M-1994 Pa ge 32 of 102 A datum t arget line is indic a ted by the ta rge t poin t symbol “X” on t he edge view o f the su rfac e and b y a phantom li ne on the surface v iew. If the loc ating p ins a re cylindric al, th en the datum target l ine is al on

g the tangency where

the pin s meet the part. The p in s may also be knife-edged. A surfac e is oft e n plac ed at 90º to t h e pi n to crea te th e datum re fe ren ce frame. T h e Fi xture Set u p The Draw ing 50 Y1 Y1 50

Y

PA RT LOCA TING PIN

Geometric D imens ioning & To le ranc ing ASME Y14.5M-1994 Page 33 of 10 2 Ex amp le 1 F rom AS ME Y 14. 5M-199 4, p 7 8 10 3 20 C1 A1 B1 B 2 A2 A3 C2 A 40 100 n 38 15 15 45 o 45 o B2 A3 A1 B1 A2 C2 C1 4 X n 6 .3 -6 .4 j n 0 .1 m A B C Geometric D imens ioning & To le ranc ing ASME Y14.5M-1994 Pa ge 34 of 102 3 .10. Partia l Datum Surface A p orti on of a su rf a ce may be used as a da tu m. F o r e xampl e , this may be d one when a part ha s a hole or grou p of hol e s at one end w here it may not be nec essary to est a blis h th e e nti re su rf a ce as a da tum to effectiv e ly loc a te the features. Th is may be accomplis hed on a drawing usi ng a chain li ne dimen si oned w ith ba sic di mens ion s to sho w the lo ca tion and e xtent of the pa rt ial dat um surfac e . T h e datu m feature symbol is attac hed to the chain l ine . The datum plane i s the n estab lished at the loc ation of th e cha in li ne . ₅₂ 12 26 THE DR AWIN G THE FIXTUR E SETU P CHA IN LI NE DA TUM F E A T UR E A THEORETI CA LL Y EXA CT DA TUM PL A N E SIM U LA T E D DA T U M (F IX TU RE SUR F A C E)

Geometric D imens ioning & To le ranc ing ASME Y14.5M-1994 Page 35 of 10 2 3

.11. Exercise _1. List the 3 primary

item

s that are

consi

d

er

ed Datum features on an object or part.

__ ____________ ____________ ____________ ____________ ____________ ___ 2. Draw the sy m

bol that is known a

s

the Datum Reference Sy

m bol. 3. The primary datum requires a m inim um of _______ __ points. The second ary datum requires a m inimum of _________ points. The tertiar y datum requires a m inimum of _____ ____ points. 4.

Below are exam

ples of

a hole (Figure 1) and a pin (

Fig

ure 2

) that will be

identified as

datum features. Sketch on t

he figure and e

xplain how the datum

axis for each would

be det ermi ned . 5. Geometric D imens ioning & To le ranc ing ASME Y14.5M-1994 Pa ge 36 of 102 On the foll owing, F igure 3 , ident ify

the: datum feature,

part, sim ul ate d datum , and the datum plane. a)__ ________________ b) _____________ _____ d)______________ ____ c)________ __________ Figu re 3

On the following exercises, using

the drawing provided on next p ag e (F ig ure 4), 6. Specify the le ft hand e d ge as Datum A . 7. Specify the ∅ 12 hole as Datum D . 8.

Specify the right hand

edge a s D atum G. 9. On the bottom surfac e, specify a partial Datum K

over a distance of 40 from

the right

edge of the p

art.

10. Specify the right hand

edge of the 13 slot as Datum M.

11. Specify the 13 slot as Datu

m P.

12. Specify the two

∅

6 holes as Datum

S.

13. Datum feat

ur

es may be either features of size or

features without s ize. On the drawing , identify featu res of size by pl

acing a ‘Z’ next to them

, and identify the

fe ature s without size b y pla cing a n ‘x ’ ne xt to them.

Geometric D imens ioning & To le ranc ing ASME Y14.5M-1994 Page 37 of 10 2 151 50 114 25 32 51 6 THR U 2X 16 13 70 16 12 THRU Figure 4 Geometric D imens ioning & To le ranc ing ASME Y14.5M-1994 Pa ge 38 of 102

14. What is the relationship between the center pla

ne of the slot

and the center plane of the

part? W ha t is the tota l loca tion tole rance that the c ente r plane of the slot va ry from the ce nter pla ne of the

part? Is design inten

t clear? 14 + 1 20+ 0.5 40+ 1 7+ 0.5

PLUS/MINUS

METH

O

D

A

POSITIONAL

METHOD

FU

NCTIONA

L

GAGE

Geometric D imens ioning & To le ranc ing ASME Y14.5M-1994 Page 39 of 10 2 The pi

cture below represents a cast part. It was determined

that

the part should have

datum targ ets specified to standard ise the in it ial m achi ning

set-up. On the drawing nex

t

pag

e, ske

tch the datum targ

ets in proper fo rmat as y ou would ex pect to see them on an engineering drawing. Surf ace X should have three ∅ 10 target pads, Surfac e Y should

have two targ

ets lines of

c

ontact

and Surface Z shoul

d have one p oint of contact. Arran ge

these targets on the in

dicated s

urfaces to

your preference. Show all basic dimensions and

just estimate the distances.

Geometric D imens ioning & To le ranc ing ASME Y14.5M-1994 Pa ge 40 of 102 Z X Y 1.18 0.39 0.69 0.49 0.28 X 0.39 2.76 3 80 70 12.5 10 10 17.5 30 7

Geometric D imens ioning & To le ranc ing ASME Y14.5M-1994 Page 41 of 10 2 152 24 74 0 0 74 24 120 128 96 64 50 24 20 20 64 50 24 Ø 38.5 - 40.0 C B A M Ø 0.4 B C 28 A

Understanding Datum Reference

Frame Application (DRF)

Example 1

A Ø 0.12 Y X Y Z

Degrees of

Freedom Matri

x

Rx

Ry

Rz

Tx

Ty

Tz

Datum

Fe

atures

Geometric D imens ioning & To le ranc ing ASME Y14.5M-1994 Pa ge 42 of 102 152 24 74 120 128 74 24 120 128 96 64 50 24 20 20 64 50 24 Ø 38 .5 - 40 .0 B C 28 A

Understanding Datum Reference

Frame Application (DRF)

Example 2

A B C M Ø 0.4 A 2 Ø 0.1 Y X Y Z

Degrees of

Freedom Matri

x

Rx

Ry

Rz

Tx

Ty

Tz

Datum

Features

Geometric D imens ioning & To le ranc ing ASME Y14.5M-1994 Page 43 of 10 2 24 74 46 74 24 46 24 24 B C A

Understanding Datum Refer

ence

Frame Application (DRF)

Example 3

Ø 19.0 - 19.3 B D A M Ø 0.25 Y X Y Z D M B A What effec t d oes th e MMC Modif ier have i n thi s sec ond FC F arrangement? D 50 50 Ø 38.5 - 40.0 C B A M Ø 0.4 A Ø 0.12 Rx Ry Rz Tx Ty Tz Datum Features Geometric D imens ioning & To le ranc ing ASME Y14.5M-1994 Pa ge 44 of 102 48 74 46 74 48 46 24 24 B C A

Understanding Datum Ref

erence

Frame Application (DRF)

Example 4

Y X Y Z E Ø 0.98 22.2 - 2 2.5 A E D M Ø 0.25 1. 2. 3. E M A D E M A M D 50 50 D Ø 38.5 - 40 .0 C B A M Ø 0.4 A Ø 0.12 Ø 19.0 - 19.3 B D A M Ø 0.25 Rx Ry Rz Tx Ty Tz Datum Features

Geometric D imens ioning & To le ranc ing ASME Y14.5M-1994 Page 45 of 10 2 48 74 46 74 48 46 25.5 6 24 B C A

Understanding Datum Reference

Frame Application (DRF)

Example 5

Y X Y Z G 50 50 Ø 0.9 8 22.2 - 22.5 B D A M Ø 0.25 D Ø 38. 5 - 40.0 C B A M Ø 0.4 A Ø 0.12 Ø 19.0 - 19.3 B D D - G A M Ø 0.25 Degrees of Freedom Matri x Features Geometric D imens ioning & To le ranc ing ASME Y14.5M-1994 Pa ge 46 of 102 4. Form T o lerance 4 .1 . Straigh tness Li n e El em en t – P lan e Su rfa ce 0.05 0.1 ON THE D R A W IN G ME A N IN G 0.1 To le ra nc e 0.05 Tolerance

Each longitudinal element of the surface m

ust lie

between two parallel lines

0.0

5 apart in the left view

and 0.1 in the right view of

Geometric D imens ioning & To le ranc ing ASME Y14.5M-1994 Page 47 of 10 2 L in e El em en t – C yl in d e r A xi s at Regardles s of Fe ature Si ze (RFS) The d eri ve d m ed ia n lin e

of the feature’s actu

al lo

ca

l s

ize

m

ust lie with

in a cy lindrical tol er an ce zone of 0.04 dia m eter, regardle

ss of the feature size. E

ach circular elem en t of the surface m us t be w ithin th e speci fied lim its of size. ON TH E DRAWI N G MEANI NG 0.02 w ide tol erance zone 0.02 w ide tolerance zone 0. 02 w ide tolera nce zone n 1 6 .0 0 M M C n 1 6 .0 0 M M C n 1 6 .0 0 M M C (a ) (b) (c) n 16 .0 0 15 .8 9 0.0 2 Each long it ud inal ele m ent of th e s urface m us t li e bet w ee n tw o parallel lin es 0.02 apar t where t he tw o lin es a nd the no mi nal ax is o f th e p art shar e a speci fied lim its of si ze and th e bou ndary of perfect for m at MMC 16 .00 N

ote: Waisting (b) or barreli

ng (c ) of t he surface, th ough with in t he s traigh tness toleran ce, m ust not e xceed the li m its of size of th e f eat ure ON THE DRA WI NG M E A N IN G n 1 6 .0 0 0.04 diameter tol e ra nce z o ne n 1 6 .0 4 outer b ound ar y n 0 .0 4 n 16.00 15.89 Geometric D imens ioning & To le ranc ing ASME Y14.5M-1994 Pa ge 48 of 102 Axi s at M aximum M a teri a l Co nditio n (MMC) Acceptance Boundary ON THE DRA W IN G n 1 6 .0 4 V irt ual C ondi tio n ME A N IN G Fea ture D ia me te r tole ra nc e Si ze zo ne a llow ed 16 .0 0 0. 0 4 15 .9 9 0. 0 5 15 .9 8 0. 0 6 15 .9 0 0. 1 4 15 .8 9 0. 1 5 n 0 .0 4 m n 16. 00 15. 89 The de rive d m edia n line of th e feat ure ’s ac tual l ocal size m ust lie within a cy lindrical to leran ce zo ne of 0. 04 diam ete r at MMC. As each actu al lo ca l s ize d ep arts fro m MMC, an in cr ease in th e local d ia m eter of the to leran ce cy lind er i s allo wed w hic h is e qu al to th e am ou nt of such d epar ture. E ach circular el em ent of the surface m ust be with in th e specified l im it s of s ize. n 1 6 .0 0 n 1 6 .0 0 n 1 6 .0 4 n 1 6 .0 4 n 0 .0 4 n 1 6 .0 4 n 1 5 .8 9 n 0 .1 5

•

The m ax im um diam eter of t he pin w ith perfect f or m is show n i n a g age w ith a 16.04 di am et er ho le.

•

With t he pi n at m axi m um dia m eter 16. 00, the g ag e will accept th e p in w ith u p to 0.04 va riati on in straightness.

•

With th e p in at m ini m um di am eter 15 .8 9, the g ag e will accept th e p in w ith u p to 0.15 va riati on in straightness.

Geometric D imens ioning & To le ranc ing ASME Y14.5M-1994 Page 49 of 10 2 Pe r Unit Le ngth 4. 2. F la tn es s O N THE DRA W ING ME A N IN G n 16 .0 0 15 .8 9 1 0 0 n 0. 4 n 0 .1/25 1 0 0 2 5 n 16 .0 4 ou ter bo un dary n 15 .8 9-16 .0 0 n 16.04 to le ra nc e z one n 0. 1 tol erance z o ne in e ach 25 mm of l e ng th The de rive d m edia n li ne of the f eatur e’s actu al lo ca l size mus t li e wi th in a cy lindrical tol eran ce zo ne of n 0.4 for the total 100 m m of leng th an d w ith in a 0.1 cy lindrical tol eran ce zo ne for any 25 mm leng th, reg ar dl ess of featu re size. E ach circu la r el em ent of the surface m ust be within t he specified limits of size. 0. 25 w ide t o le ra nc e z on e 0. 25 ON TH E DR AW IN G M E A N ING The surface mus t li e b etw ee n tw o para ll el p lan es 0.25 ap art. The su rfa ce m ust be with in th e specifie d lim its of size . Geometric D imens ioning & To le ranc ing ASME Y14.5M-1994 Pa ge 50 of 102 4 .3 . Ci rcularit y (Rou ndness) 4. 4. Cy lin d ri ci ty ON THE DRA W ING ME A N IN G A A 0.25 w ide toler anc e z o ne SE CT ION A -A 90 0.25 ON TH E DRA WI NG ME A N IN G SEC T ION A-A 0.25 w id e tole ra nce zone 0.2 5 Sn 19.2+ 0 .5 A A Each cir cular elem en

t of the surface in a plan

e p erpendicular to an axis m ust lie b etween two con ce ntri c circles, on e h aving a r adi us 0.25 la rg er th an th e o th er. Each ci rcu lar ele me nt of the surf ac e m ust be with in th e specifie d lim its of size . Each ci rc ular ele m en t of the su rfac e in a pla ne pa ss in g through a comm on ce nter m ust li e b etw een tw o concentr ic cir cles, o ne having a r ad ius 0.25 larg er th an t he oth er. E ach cir cular el emen t of th e su rface m us t b e w ithin th e sp ecified li m its of size. ME A N IN G 0. 25 w ide t olera nce z one ON THE DRA WIN G n 25. 0 +0 .5 0.2 5 The cy lindrical surface m ust lie b etw ee n tw o co ncentric cy linders, one h aving a r adiu s 0.25 larg er th an th

e other. The surface

m ust be wi th in the specif ied li m its of size.

Geometric D imens ioning & To le ranc ing ASME Y14.5M-1994 Page 51 of 10 2 4. 5. E x er ci se 1. On Figure 1(a), indicate contro l of elem ent straig htness by use of Rule # 1 so that

maximum possible error is no more th

an mm if the feature m axi mum size is ∅ 16m m. 2. On F ig ure 1(b), indica te an elem en t straight ness maximum of 0.0 12mm . 3.

What is the circularity

(rou ndness ) of this pin? ________ ____ ____________ ___ 4. On Figure 1(c), indica te that axis

straightness may violate

Rule #1 and allow a total be nd of up to 0.4m m. 5. On F ig

ure 1(d), assume that the pin will assemble with the hole sho

w

n in 1 (e).

The condition

of ______________ is often

desired. Indicate this with a straightness

tolerance of 0.4mm.

6.

What is the cylindricity of this p

in? ___________________

7.

What is the V

irtual Condition of the pi

n for the require

m ent of question 5? _ ____ 8. On Figure 2, indicate on the b ottom surf ac e a con trol that requ ires all elem ents and poi nts relative to eac h other be wi thi n a toleranc

e zone that is two

pl anes w hich are 0.05mm a pa rt. This co ntrol woul d b e called ___ ____________ _____ Geometric D imens ioning & To le ranc ing ASME Y14.5M-1994 Pa ge 52 of 102 Ø 16.00 - 15.97 Ø 16.00 - 15.97 Ø 16.0 - 15.9 Ø (Virtua l C on dition )

Figure 1

(d ) (a) (b) (c) (e)

Geometric D imens ioning & To le ranc ing ASME Y14.5M-1994 Page 53 of 10 2 3030

°

45 45 ± 0. 4 45 18 ± 0. 4 110. 00 110 ± 0. 6 45 40 ± 0. 4 45 20 ± 0. 4 28

°

Ø 12 + 0. 1 - 0

MAIN VIEW

Figure 2

Geometric D imens ioning & To le ranc ing ASME Y14.5M-1994 Pa ge 54 of 102 5. Orient ation T o le rance 5 .1 . Pa rallelism S u rf ace Pl an e The surface mus t li e b etw een tw o parallel p lan es 0.12 a part which ar e par al le l to d atu m plan e A. The surface mus t b e with in th e sp eci fied li m it s o f size. A xis re la te d t o a S u rf ac e Pla n e Reg ardl es s of featur e si ze, th e featu re ax is m us t lie b etw een tw o paral lel pla nes 0.12 ap ar t w hi ch are p aral lel to datu m p lane A. The f eatur e ax is mus t b e w ith in th e sp ecified tol eran ce of lo cat ion . What wou ld be the res ult if a dia m ete r symbo l wa

s added to the callout?

A Ø 0 .1 2 MEA NING O N T H E DRA W IN G 0. 12 A f A Pos sible or ient at ion of th e sur fac e 0. 12 w ide t oler anc e zone _Dat um Plane A MEA NI NG O N T H E DRA W ING 0. 12 A f A 0. 12 w ide tole rance zone Da tum Plane A P os si bl e or ie nt at ion of fe ature ax is