What is "true position" according to GDandT?

• A. The nominal dimension of a feature
• B. The exact theoretical location of a feature as defined by its geometric tolerance
• C. The average position within a specified tolerance
• D. The point at which maximum material condition is achieved

Answer: (B)

True position in GD&T is defined as the exact theoretical location of a feature as specified by its geometric tolerance. This concept is crucial because it allows designers and manufacturers to ensure that features on a part align with each other as intended, despite any variations that may occur during the manufacturing process.

True position is used to control the location of features with respect to a datum or a set of datums. It defines a target area that the actual feature must fall within, which is established by applying the allowable tolerances specified in the geometric tolerance note. This ensures that even if there are slight deviations in the manufacturing of the part, it can still be assembled correctly if the features meet the requirements of true position.

Since true position is a theoretical concept, it does not account for actual functional variations or even the nominal dimension of a feature. It is fundamentally about ensuring precise control over where the features should be located for proper function, assembly, and overall part quality.