Surface plate
Sine bar width
Sine bar length
Slip gauges height
Developing inaccuracies
Bright spots will be visible
Obstruct component movement
Lapping compound will be sticky
Workpiece will cut the lap
Accuracy can't be obtained
Lap will cut the workpiece
Lapping operation leaves high spots
Cast iron
Aluminium
Bronze or zinc
Copper or brass
To reduce cost
To reduce time
To keep close tolerance
To reduce maintenance cost