Question

What is the effect of pitch error upon the effective diameter of a screw thread?

(a) D1 = E x K

(b) D1 = 2E x K

(c) D1 = E x K/2

(d) D1 = E x K x 4

I have been asked this question in class test.

I'm obligated to ask this question of Screw Thread Gauge Tolerance topic in chapter Metrology of Screw Thread, Gauges for ISO Metric Screw Threads of Engineering Metrology

Answer 1

Correct option is (a) D1 = E x K

Easy explanation: The compensations for pitch and angle errors are also provided for by the application of corrections for each of these quantities. Effect of pitch error upon effective diameter of a screw thread is

 D1 = E x K where D1=Effective dia. equivalent of pitch error, E = max. cumulative pitch error along the thread, K = constant for the shape of thread.