Subject:- Metrology and Quality Engineering

Topic:- Screw Thread measurement

Difficulty:- Low

Working Procedure:-

The gear tooth vernier has two vernier scales and they are set for width ‘W’ of the tooth and depth‘d’ from the top at which ‘W’ occurs. Consider one gear tooth, the values of ‘W’ and ‘d’ can be found by using caliper. It may be noted that ‘w’ is chord length but tooth thickness is specified by arc distance. Also ‘d’ found out by using caliper is slight greater than addendum. Therefore ‘W’ and ‘d’ are called chordal thickness and chordal addendum respectively. Take five readings of ‘W’ and‘d’ and calculate ‘Wavg’ and ‘davg’. With the help of ‘Wavg’ calculate the experimental value of module. Calculate theoretical value of the module. Finally find out percentage error in module.