Question

For a diameter of 20mm, several pitches given are 1, 1.5, 2 and 2.5mm. Which of the following is coarse pitch?

(a) 1mm

(b) 2 and  2.5mm

(c) 1.5, 2 and 2.5mm

(d) 2.5mm

I have been asked this question in a national level competition.

This question is from Diameter and Pitch Combinations in section Metrology of Screw Thread, Gauges for ISO Metric Screw Threads of Engineering Metrology

Answer 1

Right choice is (d) 2.5mm

The explanation is: For the diameter of 20 mm various pitches allowed are 1, 1.5, 2 and 2.5 mm. Of these 2.5 is coarse pitch, and the 1, 1.5 and 2 are fine pitches. Only largest of the pitches falls under coarse pitch and other remaining comes under fine pitches.