This document provides information on geometric dimensioning and tolerancing (GD&T) symbols, tolerance zones, gauging, surfaces, and features of size. It includes a chart that defines common GD&T terms such as straightness, flatness, circularity, cylindricity, parallelism, perpendicularity, profile, position, symmetry, runout, and others. The chart also indicates whether each term applies to size, location, orientation, form or distribution/evenness and how they are gauged on surfaces or features of size.

1. ORIENTATION
FORM
LOCATION
PROFILE
RUNOUT
A
A
0.03
0.03
0.03
0.03
0.03
10±0.050
10±0.05
A
A
0.03
0.03
0.03
0.03
25.0
25.0
Two parallel planes
0.03 apart
Two concentric circles
0.03 apart
Two parallel lines
0.03 apart
Two parallel planes
0.03 apart
parallel to datum
Two parallel planes
0.03 apart
Datum A
Axis
Tolerance Zone
at
10±0.05
10±0.05
0.03
M
Cylindrical Tolerance Zone
0.03 when Part ∅ = 10.05
0.13 when Part ∅ = 9.95
Datum A
Datum A
60°
Datum A
Datum A
Two concentric cylinders
0.03 apart
Two parallel planes
0.03 apart
Uniform Linear Boundary About True Profile
0.03 apart
Datum B
Datum A
Datum A
Tolerance Zone
Uniform Surface Boundary About True Profile
0.03 apart
Datum B
Part
Gauge
Datum axis
Measured axis
0.03
Diameter Symbol is required
Can also be used
on flat surfaces
perpendicular
to the datum axis
Can also be used
on flat surfaces
perpendicular
to the datum axis
A
A
A
0.03
0.03
A
Two parallel planes
0.03 apart
A
Datum A
Fixed axially
+ Rotated
A
Datum A
Fixed axially
+ Rotated
Datum A
Fixed + Rotated
A
A
Gauge must
follow true profile.
Profile is usually
measured with a CMM.
Gauge ID = 10.08
Cylinder Gauge ID = M +
60° Gauge
Block
60°
Gauge must
follow true profile.
Profile is usually
measured with a CMM.
90°
Gauge pin
inserted
perpendicular
to datum
Pin Gauge ∅ = 9.92
(9.95 - 0.03)
Pin Gauge OD = M −
0.03
Part (actual) position
True
center
Measure X and Y location and compare to the true position.
This formula must be less than
the ∅ True Position tolerance
(ActualX-True X)2
+(Actual Y-True Y)2
√
Y
X
Actual Y
True Y
Actual X
True X
Actual
Hole Position
True
position
Tolerance Zone
of Pin Gauge
Actual
True
60°
A
A
A
A
A
A
A
A
B
B
A
A
B
B
A
A
A
A
A
0.03 A
A
B
B
C
C
M
0.03 M
0.03
Flat datum block
(Datum A)
Gauge kept parallel to datum
Flat datum block
(Datum A)
Gauge kept perpendicular to datum
Part
Gauge
0.03 M
Planar Tolerance Zone
Two parallel planes
0.03 apart
= 10.08
M +
Gauge spacing
at Virtual Condition
Actual
Pin Position
True
position
Tolerance Zone
of Hole Gauge
Gauge Hole ∅ = Virtual Condition
(Largest Pin Size [MMC] + Position Tol.)
Datum A
Fixed + Rotated
A
1
The following is usually
done with a CMM:
1. Determine
Datum axis
2. Measure referenced
surface
3. Determine if central
axis falls in TZ
The following is
usually done
with a CMM:
1. Determine
Datum plane
2. Measure both
surfaces of features
3. Determine if
midpoints fall in TZ
Datum A
Plane
A
20.0
10±0.05
A B
B
C
C
0.03
30.0
A
0.03 M
90°
Basic dimensions (not shown) are required to
define the True Profile when datums are used.
Basic dimensions (not shown) are required to
define the True Profile when datums are used.
2X
FUNCTIONAL
GAUGING
For an
External
Feature
For an
Internal
Feature
Gauge Pin ∅ = Virtual Condition
(Smallest Hole Size [MMC] - Position Tol.)
1
Multiple datums
may be used
to specify
Perpendicularity
L O
F
L OF
F
(Derived Median
Line and Plane)
X
X W U
Z X
V
Y
Z X
Y
W U
Z X
V
Y
Z X
Y
W U
Z X
V
Y
Z X
Y
W U
Z X
V
Y
Z X
Y
OF
W U
Z X
V
Y
O
W U
Z X
V
Y
L OF
(Derived
Median
Points)
S L OF
X
X
Size
Z X
Y
Location
W U
Z X
V
Y
Orientation Form
Distribution/
Evenness of
Form Only
None
Straightness
(Surface)
Flatness
(Surface)
Circularity
Cylindricity
Parallelism
Straightness
(Derived Median Line w/ )
M
Perpendicularity
(Feature of Size w/ )
M
Perpendicularity
(Feature)
Angularity
Profile
of a line
True Position
Concentricity
Symmetry
Runout
Total Runout
Profile
of a surface
True Position
(Maximum Material
Condition)
Flatness
(Derived Median
Plane w/ )
M
M
M
M
M
SYMBOL NAME TOLERANCE ZONE GAUGING SURFACES FEATURES OF SIZE
All drawings made in
first angle projection
ON DRAWING
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Provided by GD&T Basics - www.gdandtbasics.com
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