Summarize the relationship between (minimum) achievable dimensional tolerance and part size.

• A. As part/feature size increases, the minimum achievable tolerance increases
• B. As part/feature size increases, the minimum achievable tolerance decreases
• C. There is no relationship between size and tolerance
• D. Tolerance improves with material hardness

Answer: (A)

When you look at how tightly a part can be held, the size of the feature sets the practical limit. In manufacturing, the tools, machines, fixtures, and measurement systems all have fixed accuracy and stiffness. As feature size grows, those small errors—tool deflection, thermal expansion, fixture misalignment, machine backlash, and measurement uncertainty—tend to accumulate over the larger dimension. That means the smallest tolerance you can reliably achieve gets larger for bigger parts or features. So, larger parts typically require looser tolerances.

This idea doesn’t come from material hardness; hardness isn’t what governs dimensional control in this context.