Which of the following component need hand lapping?

Explanation:

Lapping:

• It is an abrading process for refining surface finish and the geometrical accuracy of flat cylindrical and spherical surfaces
• It is a process or removing surface roughness, tool marks, surface cracks from grinding, slight distortions and other minor – defects from previous operations
• Lapping produces geometrically true surfaces, corrects minor surface imperfections, improves dimensional accuracy and provides a very close fit between two contact surfaces

Hand Lapping

Hand lapping operations can be divided into:

1. lapping flat surfaces
2. lapping internal cylindrical surfaces
3. lapping external cylindrical surfaces

Machine Lapping

Hand lapping is useful for lapping a few components only. For batch production lapping work, lapping machines are used.

There are three types of lapping machines commonly used ae as follows:

1. Bonded abrasive circular plate lapping machine for flat and circular components
2. Bonded abrasive or cast iron wheel machines for centerless lapping 
3. Internal cylindrical lapping machines

Press work dies are mot manufacturers in mass production, therefore hand lapping is used in it.