Geometric Tolerancing

Geometric Tolerancing is used Things like:

•Straightness •Flatness •Circularity •Cylindricity

•Angularity

Geometric Tolerances are shown on a to specify the shape of features. •Profiles

•Perpendicularity •Parallelism •Concentricity •And More...

drawing with a feature control frame.

The Feature Control Frame

Geometric Tolerancing Perpendicular

This feature control frame is read as: "The specified feature must lie perpendicular within a tolerance zone of 0.05 diameter at the maximum material condition, with respect to datum axis C. In other words, this places a limit on the amount of variation in perpendicularity between the feature axis and the datum axis. In a drawing, this feature control frame would accompany dimensional tolerances that control the feature size and position.

Geometric Characteristic Symbols

TYPE OF TOLERANCE

CHARACTERISTIC

SYMBOL

SEE:

STRAIGHTNESS

-

6.4.1

INDIVIDUAL FEATURES

FORM

FLATNESS

CJ

6.4.2

CIRCULARITY (ROUNDNESS)

O

6.4.3

CYLINDRICITY

//

6.4.4

INDIVIDUAL

PROFILE

PROFILE OF A LINE

r^

6.5.2 (b)

OR RELATED FEATURES

PROFILE OF A SURFACE

6.5.2 (a)

ANGULARITY

6.6.2

ORIENTATION

PERPENDICULARITY

_L

6.6.4

PARALLELISM

//

6.6.3

RELATED FEATURES

POSITION

5.2

LOCATION

CONCENTRICITY

©

5.11.3

SYMMETRY

5.13

RUNOUT

CIRCULAR RUNOUT

6.7.1.2.1

TOTAL RUNOUT

6.7.1.2.2

♦ ARROWHEADS MAY BE FILLED OR NOT FILLED

13.3.1

FIG. 3-1 GEOMETRIC CHARACTERISTIC SYMBOLS

A feature control frame gives information about geometric tolerances on the feature. 15

Straightness Example

THIS ON THE DRAWING

MEANS THIS (a)

0.02 wide tolerance zone

016.00 MMC

— 0.02 wide tolerance zone

016.00 MMC

Each longitudinal element of the surface must lie between two parallel lines (0.02 apart) where the two lines and the nominal axis of the part share a common plane. The feature must be within the specified limits of size and the boundary of perfect form at MMC (16.00).

Note: Waisting (b) or barreling (c) of the surface, though within the straightness tolerance, must not exceed the limits of size of the feature.

Straightness at MMC

Straightness Datum

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Responses

  • Vigo Twofoot
    How do you specify geometric tolerances using symbols and notes?
    8 years ago
  • JASMINE
    What are perpendicular lines?
    8 years ago
  • maik
    How to check concentricity perpendicularity run out position total run out flatness?
    7 years ago
  • Zainab Brown
    How do draw sketch circularity?
    7 years ago
  • marguerite cahill
    How to calculate feature in a part engineering drawing?
    7 years ago

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