Question

The following diagram shows part of a screw gauge. What is the reading?

• A. 1.80 mm
• B. 1.83 mm
• C. 1.86 mm
• D. 1.89 mm

Answer 1

The correct option is C

1.86 mm

First part of the measurement, P.S.R = 1.5 mm

Head scale division that coincides with the pitch scale axis, H.S.C = 36

Second part of the measurement, H.S.C $\times$ L.C = 36 $\times$ 0.01 mm = 0.36 mm

Measurement with zero error = P.S.R + H.S.C $\times$ L.C = 1.5 + 0.36 = 1.86 mm