In its basic form, a micrometer is C-shaped with a fixed anvil on one end of the open C and a movable spindle on the other.

A micrometer is a G clamp with jaws in its most common form around 25 mm in size, and with a very accurately calibrated screw thread. It has a handle with both a scale in millimetres or inches ...

and easily-made apparatus of the micrometer form may be constructed as follows: Get a common iron or brass bolt about y of an inch in diameter and about 2% inches long, with as fine a thread as ...

In this case as with all micrometers it’s possible to overshoot the zero and damage the thread if you apply too much force, but just on the ratchet it would land in the same place. A pass on a ...