Question

A constant ‘K’ is used for defining the shape of thread. What is the value of ‘K’ for Whitworth?

(a) 1.5

(b) 1.62

(c) 1.73

(d) 1.92

The question was asked in semester exam.

Origin of the question is Screw Thread Gauge Tolerance topic in division Metrology of Screw Thread, Gauges for ISO Metric Screw Threads of Engineering Metrology

Answer 1

Right option is (d) 1.92

Easy explanation: Effect of pitch error upon the effective diameter of a screw thread is  D1 = E x K,

 K = constant for the shape of thread = 1.92 for Whitworth, = 1.73 for International metric threads and = 2.27 for B.A.