Question

Which of the following item must fall within the prescribed limit for plug gauges?

(a) Measured effective diameter along the pitch line

(b) Measured effective diameter perpendicular to the pitch line

(c) Measured minor diameter along the pitch line

(d) Measured minor diameter perpendicular to the pitch line

I have been asked this question during an interview.

This interesting question is from Screw Thread Gauge Tolerance in portion Metrology of Screw Thread, Gauges for ISO Metric Screw Threads of Engineering Metrology

Answer 1

Correct choice is (a) Measured effective diameter along the pitch line

Best explanation: There are some requirements on effective dia which must be met before the gauge can be accepted i.e. the measured effective diameter along the pitch line and the measured effective diameter is +ΔE1+ΔE2 for plug gauges.