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