Characteristic
And Symbol
Flatness
Basic definition
Tolerance zone shape
A two dimensional tolerance zone
defined by two parallel planes
within which the entire surface
must lie.
Datum
Refer.
None
Implied
Condition
RFS
Allowable
Modifiers
Key Points
None
Compares to a
perfect
counterpoint of
itself.
None
No particular
orientation
Compares to a
perfect
counterpoint of
itself.
(e.g. straight line)
Total width
A condition where an element of a
surface or an axis is a straight line.
Form Tolerances
Straightness
Total width
None
RFS
Additive to size
when applied to
an axis.
Compares to a
perfect
counterpoint of
itself.
Cylindrical
Circularity
Cylindricity
A condition on a surface of
revolution (cylinder, cone, sphere)
where all points of the surface
intersected by any plane
perpendicular to a common axis
(cylinder, cone) or passing through
a common center (sphere) are
equidistant from the axis of the
center.
A condition on a surface of
revolution in which all points of
the surface are equidistant from a
common axis.
Total width tolerance
zone between two
concentric circles.
Total width tolerance
zone between two
concentric cylinders.
None
RFS
None
Not additive to
size or location
limits.
None
RFS
None
Applies over
entire surface.
Like wrapping
“flatness” around
cylinder
Very expensive,
consider using
Runout
Profile Tolerances
Profile of a line
Profile of a
surface
Orientation Tolerances
Angularity
A uniform two dimensional zone
limited by two parallel zone lines
extending along the length of a
feature.
A uniform three dimensional zone
contained between two envelope
surfaces separated by the tolerance
zone across the entire length of a
surface.
The distance between two parallel
planes, inclined at a specified basic
angle, in which the surface, axis, or
center plane of the feature must lie.
Total width: can be
applied bi-directionally
or uni-directionally to
either side of profile.
Total width: can be
applied bi-directionally
or uni-directionally to
either side of profile.
Total width
Optional
Optional
RFS
LMC or MMC
on datum ref if
feature of size
The profile being
controlled is
defined by Basic
dimensions or by
equation.
RFS
LMC or MMC
on datum ref if
feature of size
(FOS)
The profile being
controlled is
defined by Basic
dimensions or by
equation.
LMC or MMC
on feature if
FOS.
Yes
RFS
LMC or MMC
on datum ref
if FOS
Cylindrical
Perpendicularity
The condition of a surface, axis,
median plane, or line which is
exactly at 90 degrees with respect
to a datum plane or axis.
Total width
LMC or MMC
on feature if
FOS.
Yes
RFS
LMC or MMC
on datum ref
if FOS
Cylindrical
Parallelism
The condition of a surface or axis
which is equidistant at all points
from a datum of reference.
Total width
Cylindrical
LMC or MMC
on feature if
FOS.
Yes
RFS
LMC or MMC
on datum ref
if FOS
Relation to more
than one datum
should be
considered to
stabilize the
tolerance zone in
more than one
direction.
Relation to more
than one datum
should be
considered to
stabilize the
tolerance zone in
more than one
direction
Relation to more
than one datum
should be
considered to
stabilize the
tolerance zone in
more than one
direction
Runout
Runout: Circular
Location
Runout: Total
Concentricity
A composite tolerance used to
control the relationship of one or
more features of a part to a datum
axis during a full 360 degree
rotation about the datum axis.
Each circular element of the
feature/part must be within the
runout tolerance.
A cylindrical tolerance zone whose
axis coincides with the datum axis
and within which all crosssectional axes of the feature being
controlled must lie. (Note:
Concentricity is very expensive
and time-consuming to measure.
Recommended that you try
position or runout as an alternative
tolerance.)
Defined by the full
indicator movement
(FIM) along an
independant circular
element when a feature is
rotated 360 degrees.
Defined by the full
indicator movement
(FIM) along all circular
elements across the entire
feature when that feature
is rotated 360 degrees.
Defined by a cylindrical
tolerance zone whose
axis coincides with the
datum axis and within
which all cross-sectional
axes of the feature being
controlled must lie.
Yes
Yes
RFS
RFS
None
None
Can be defined as
the relationship
between two
features.
Relatively
inexpensive to
implement.
Can be defined as
the relationship
between two
features.
Relatively
inexpensive to
implement.
Must compare
axes.
Yes
RFS
None
Very epensive to
implement.
Use position,
profile, or runout
instead if possible
Location
A zone within which the center,
axis, or center plane of a feature of
size is permitted ton vary from its
true (theoretically exact) position.
Position
Total Width
Cylindrical
Yes
RFS
MMC or LMC
on the tolerance
if the tolerance
is applied to a
feature of size
or on a datum
reference if the
datum is a
feature of size.
With the MMC
modifier:
Permits functional
gage inspection.
Allows additional
tolerance based
upon size.
Relatively
inexpensive to
implement.