During a hardware inspection, a reduction of what percentage or more in any specified dimension should cause removal from service?

• A. 10%
• B. 30%
• C. 45%
• D. 50%

Answer: (A)

The key idea is that wear limits are set to catch unsafe degradation before it leads to failure. If any critical dimension has decreased by 10% or more, the part no longer meets required tolerances and its strength, fit, and operating clearance can be seriously compromised. That 10% threshold provides a safety margin: as dimensions shrink, stresses concentrate, joints may loosen, and misalignment can occur, making continued use risky. For example, a pin that should be 1.0 inch in diameter wearing down to 0.9 inch reduces its cross-sectional area and can cause excessive play, increased wear on mating surfaces, or failure under load. Larger reductions (30%, 45%, 50%) would indicate obvious severe degradation, but the standard uses 10% as the point to remove from service and inspect or replace.