Question

It is found that for a screw gauge, the $5^{th}$​ division of the head scale coincides with the pitch scale axis and the zero of the head scale lie below the pitch scale axis. The least count of the screw gauge is 0.01 mm. What is the zero correction?

Answer 1

Since the zero of the head scale lies below the pitch scale axis, the zero error is positive and is given by

Z.E = + (n $\times$ L.C)

= + (5 $\times$ 0.01 mm) = + 0.05 mm

And the zero correction is given by

Z.C = – 0.05 mm