Angle of BSW 'V' form thread is

Feeler

Feeler gauges are used:
– To check the gap between the mating parts
– To check and set the spark plug gaps
– To set the clearance between the fixture (setting block) and the cutter/tool for machining the jobs
– To check and measure the bearing clearance, and for many other purposes where a specified clearance must be maintained.

Vernier caliper

Vernier height gauge works on the principle similar to Vernier caliper.

Cellulose