Question

A screw gauge is provided with a "ratchet" arrangement, in the form of a knob at the right end of the spindle. The screw should be rotated by this knob only. The purpose of the is device is-

• A. to reduce zero error
• B. to prevent backlash error
• C. to control the rate of rotation of the screw
• D. to prevent damage to the pitch of the screw

Answer 1

Answer: (D)

to prevent damage to the pitch of the screw

The ratchet slips at the instant extra pressure is applied on the screw head at the zero position. This prevents damage to the pitch of the screw.