What is a feature control frame?

What is a feature control frame?

• A. A rectangular representation that communicates the geometric tolerance, the datum references, and any modifiers for a feature.
• B. A box around the callout indicating finish.
• C. A symbol for hole size.
• D. A note listing manufacturing steps.

Answer: (A)

A feature control frame is the rectangular box in a GD&T callout that communicates the geometric tolerance, the datum references, and any modifiers for a feature. It accompanies the geometric symbol to specify exactly how a feature must be controlled: the size and shape of the tolerance zone, which datums define the measurement frame, and any modifiers such as maximum material condition or projected tolerance. The datums listed inside or associated with the frame establish the reference frame used when inspecting the part, so the tolerance is interpreted relative to those datum features. This frame is what tells you not only what tolerance is required, but how the part will be gauged and what reference points anchor the measurement. It’s not just about finish, a hole-size symbol, or a manufacturing sequence—those are unrelated to the purpose and content of the feature control frame itself.

A feature control frame is the rectangular box in a GD&T callout that communicates the geometric tolerance, the datum references, and any modifiers for a feature. It accompanies the geometric symbol to specify exactly how a feature must be controlled: the size and shape of the tolerance zone, which datums define the measurement frame, and any modifiers such as maximum material condition or projected tolerance. The datums listed inside or associated with the frame establish the reference frame used when inspecting the part, so the tolerance is interpreted relative to those datum features. This frame is what tells you not only what tolerance is required, but how the part will be gauged and what reference points anchor the measurement. It’s not just about finish, a hole-size symbol, or a manufacturing sequence—those are unrelated to the purpose and content of the feature control frame itself.