Correct option is C
Lapping is a
finishing process in which an
abrasive slurry is used between a
lap (tool) and the workpiece to achieve an extremely smooth and accurate surface finish.
If the
lap is harder than the workpiece, it will
wear down (cut) the workpiece due to the
abrasive particles embedded in the lap’s surface. This leads to
material removal from the workpiece, making it smoother and more precise.
Ideally, the
lap should be softer or equal in hardness compared to the workpiece.
A
harder lap may cause excessive material removal, reducing
control over precision.
Softer laps (e.g., made of
copper, brass, or cast iron) help hold abrasive particles and allow a
controlled cutting action.
