This is the theoretically exact size from which limits of size are determined:

Acceptable parts must not extend beyond this:

This practice considers an individual part's dimensions and tolerances and that part's relation to its related parts:

When lines intersect on a drawing at angles of this many degrees, it is customary not to dimension the angle:

Defining the datum reference frame is necessary to apply GDT principles.

This is the term for the range of tightness or looseness resulting from the allowances and tolerances in mating parts:

Specific tolerances are based on the part's function and fit.

This is the measured size of a finished part:

Nominal size is used for general identification and is usually expressed in decimals.

Unilateral tolerances have traditionally been given on angles.

This means that a feature of a finished product contains the maximum amount of material permitted by the toleranced dimensions for that feature:

Geometric dimensioning and tolerancing can simplify the inspection process.

The ISO has its own system of preferred metric limits and fits.

Geometric tolerances state the maximum allowable variations of a form or its position from the perfect geometry implied in the drawing.

Increased precision makes parts less expensive to manufacture.

Tolerance is the total amount a specific dimension is permitted to vary.

In reference to geometric tolerancing, the term "geometric" refers to forms such as planes, cylinders, and squares.

Implied 90 degree angles typically have different general tolerances applied to them than other angles covered by a general note.

Large batches of parts may use statistical methods to control quality where a sample of parts is inspected.

Tolerances of form and position are typically not used to control straightness.