How do form tolerances differ from location tolerances?

How do form tolerances differ from location tolerances?

• A. Form tolerances affect the shape of a single feature; Location tolerances govern where features are located relative to datums.
• B. Form tolerances control datum references; Location tolerances adjust feature size.
• C. Form tolerances govern alignment between two features; Location tolerances set material condition.
• D. Form tolerances specify surface finish; Location tolerances specify runout.

Answer: (A)

Form tolerances govern the shape of a single feature. They set how much the feature’s form can deviate from an ideal shape—flatness, straightness, circularity, cylindricity, or a profile—without regard to where the feature is located in the part. Location tolerances, by contrast, control where the feature sits relative to datums; they define how far the feature’s true position can deviate from its intended location within the datum reference frame. So the statement that form tolerances affect the shape of a single feature and location tolerances govern where features are located relative to datums captures the essential difference. The other options mix up what each tolerance type governs—for example, form tolerances don’t control datum references or adjust size, and location tolerances don’t set size.

Form tolerances govern the shape of a single feature. They set how much the feature’s form can deviate from an ideal shape—flatness, straightness, circularity, cylindricity, or a profile—without regard to where the feature is located in the part. Location tolerances, by contrast, control where the feature sits relative to datums; they define how far the feature’s true position can deviate from its intended location within the datum reference frame.

So the statement that form tolerances affect the shape of a single feature and location tolerances govern where features are located relative to datums captures the essential difference. The other options mix up what each tolerance type governs—for example, form tolerances don’t control datum references or adjust size, and location tolerances don’t set size.