Question

What shape is the locational tolerance zone derived by direct tolerancing from two linear planes/lines perpendicular from each other (e.g. tolerancing from the bottom and left sides)? _

Answer 1

Answer:

True Position using features of size (MMC/LMC)

Explanation:

True Position using features of size (MMC/LMC)

However, with true position you can make the tolerance referenced to several datum's as opposed to just one with axis perpendicularity. When you callout true position using datums on the face, and sides of the part – perpendicularity is controlled as well.

Surface: Perpendicularity is measured using a height gauge, similar to flatness, however, the gauge (or part) is locked to a 90° datum to measure how perpendicular the surface is. The entire surface has to be measured if it is a flat feature.

If the tolerance is preceded by a diameter symbol (⌀), the tolerance is a diameter or cylindrical shaped zone, as in the position of a hole. If there is no symbol preceding the tolerance, the default tolerance zone shape is parallel planes or a total wide zone, as in the position of a slot or profile of a surface.