What does the "GDT" control in a design drawing?

• A. Geometric controls that specify how parts fit together and their allowable variations
• B. Dimensional precision of surface finishes
• C. Mechanical properties of materials used
• D. Overall aesthetics of the product design

Answer: (A)

The correct answer indicates that GD&T, which stands for Geometric Dimensioning and Tolerancing, primarily controls the geometric features of a part and how they relate to each other. This involves specifying the allowable variations in the form, orientation, and location of features on the part, ensuring that they will fit together properly during assembly.

Using GD&T provides a clear framework for interpreting the design intent, illustrating how parts are to be manufactured and inspected. It allows engineers and manufacturers to communicate precise requirements, ensuring that parts will function correctly while accommodating potential manufacturing variances.

This focus on fitting components together and controlling variations distinguishes GD&T from other aspects of design, such as surface finish, material properties, or overall appearance, which are not the primary concerns addressed by GD&T.