Fig Projected Tolerance Zone Indicated With Chain

ment of clearance holes to provide for an extreme variation in perpendicularity of the fastener is not necessary.

5.5.2 Application. Figures 5-33 and 5-34 illustrate the application of a positional tolerance using a projected tolerance zone. The specified value for the projected tolerance zone is a minimum and represents the maximum permissible mating part thickness. or the maximum installed length or height of the components, such as screws, studs, or dowel pins. See para. 5.5.3. The direction and height of the projected tolerance zone are indicated as illustrated. The minimum extent and direction of the projected tolerance zone are shown in a drawing view as a dimensioned value with a heavy chain line drawn closely adjacent to an extension of the center line of the hole.

5.5.3 Stud and Pin Application. Where studs or press-fit pins are located on an assembly drawing, the specified positional tolerance applies only to the height of the projecting portion of the stud or pin after installation, and the specification of a projected tolerance zone is unnecessary. However, a projected tolerance zone is applicable where threaded or plain holes for studs or pins are located on a detail part drawing. In these cases, the specified projected height should equal the maximum permissible height of the stud or pin after installation, not the mating part thickness. See Fig. 5-35.

Was this article helpful?

0 0

Post a comment