And not just a general mixed-use tool. There is a tool specifically ... A: That depends on the caliper, but dial calipers do have an extra instrument that could be thrown out of calibration ...

It should always be tightened using this ratchet, to protect the thread from wear and distortion. The selection of calipers under test. Left: sub £1 plastic Vernier caliper, centre: Mitutoyo 530 ...