Question

Define zero error in a screw gange.​

Answer 1

Answer:

If zero line on circular scale does not coincide with zero on the linear scale when the screw of circular scale is fully tighten or moved, the error due to this is called zero error of the screw gauge.

Answer 2

$Answer$

When the fixed stud A and movable stud B are brought in contact without applying any under pressure , and the zero of the circular scale does not coincide with the refference line, there is a zero error.