Question

What is the function of the following in a screw gauge ?
(i) Main scale
(ii) Circular scale

Answer 1

Screw Gauge

Explanation:

The screw gauge is an instrument used for measuring accurately the diameter of a thin wire or the thickness of a sheet of metal.  It consists of a U-shaped frame fitted with a screwed spindle which is attached to a thimble.

Micrometer screw gauge has two scales, one rotating scale which can be found on its rotating cylindrical part. It is called circular scale and the other one can be found on its stationary sleeve which is called main scale. Generally least count on the main scale is 0.5 mm.