Geometric Tolerances and Dimensioning. Tolerance. Why Geometric Tolerancing and Dimensioning. To ensure interchangeability of mating parts during assembly To eliminate controversy and guesswork when drawing is interpreted
The lower and upper allowable sizes are
referred to as the limit dimensions
a. Upper limits: Larger value
b. Lower limits: Smallest value
Tolerance can be expressed in several ways:
1. A general tolerance note in the title block
between the smallest feature A
and the largest feature B.
E. Line fit
two assembled mating parts.
Allowance fit: The allowance is the tightest fit between
two mating part.
Interference fit: Is the fit that leads to interference between two assembled parts.