Correct option is C
Slip gauges (also called gauge blocks) are precision measurement tools used for high-accuracy dimensional calibration in engineering and metrology. The measuring faces of slip gauges require an extremely smooth and accurate surface finish, which is achieved through lapping.
Lapping is a super-finishing process in which abrasive particles are embedded in a soft material (such as a cast iron or glass plate), and the workpiece is rubbed against it to achieve a mirror-like surface with extremely tight tolerances.
· Provides ultra-smooth surfaces (accuracy up to 0.01 µm).
· Ensures high precision and flatness, allowing slip gauges to wring together for accurate stacking.
· Eliminates surface irregularities, improving measurement accuracy.
