micrometer caliper [1]

Instrument that measures the thickness or the diameter of relatively small parts; it produces finer results than a vernier caliper.

ratchet knob

Part that stops the finely threaded screw when the pressure on the object being measured is sufficient.

frame

Horseshoe-shaped part that supports the anvil and a graduated device from which the measurement is read.

anvil

Cylindrical part that is attached to the frame of the micrometer to support the object to be measured; the object is placed between the anvil and the spindle.

thimble

Graduated cylindrical part that is activated by the finely threaded screw and measures the thickness with precision.

spindle

Cylindrical end of the finely threaded screw.

lock nut

Ring-shaped part that locks the finely threaded screw in its final position to preserve the measurement obtained.