Micrometer

Bevel protractor

Gear tooth vernier caliper

Steel rule

Distance between outside circle to pitch circle

Distance between outside circle to root circle

Distance between pitch circle to root circle

Distance between outside to bottom point of gear

0.1 mm

0.01 mm

0.2 mm

0.02 mm

Screw gauge

Vernier caliper

Gear tooth vernier caliper

Feelar gauge

Lock the index crank in position

Eliminate counting holes each time

Fix the index plate on its correct location

Avoid the back lash of worm and Worm wheel