Question

The screw gauge is provided with a “ratchet” arrangement, in the form of a knob. The screw should be rotated using this only. The purpose of this is to:

• A. Reduce backlash error
• B. Reduce zero error
• C. Prevent damage to the pitch of the screw
• D. Control the rate of rotation of the screw

Answer 1

The correct option is C Prevent damage to the pitch of the screw

Ratchet is a small device which is used to provide a limited applied force. Installed at the end of screw gauge, ratchet acts as a safety device for instruments.