Which of the following is a consequence of over-dimensioning a sketch?

• A. It reduces manufacturing time.
• B. It can cause confusion and increase probability of the part being constructed incorrectly.
• C. It guarantees interchangeability.
• D. It eliminates the need for tolerances.

Answer: (B)

Over-dimensioning a sketch adds more measurements than are needed, which clutter the drawing and make it hard to read. When there are redundant or conflicting dimensions, the person fabricating the part may misinterpret the intent, increasing the chance the part is made incorrectly. The right approach is to include only the essential dimensions that define the part and rely on tolerances to control variation, keeping the drawing clear and unambiguous. The other ideas—that extra dimensions save time, guarantee interchangeability, or remove the need for tolerances—don’t hold: extra dimensions don’t speed production, don’t ensure parts will interchange properly, and tolerances are still necessary to govern variation.