Calibrated wires for measuring the average diameter of a thread.
The calibrated wires are supplied through a pair of frames that are mounted respectively on the fixed probe and on the mobile probe (drum) of the external micrometer.
The pair of frames is composed of a frame with one wire and a frame with two wires To obtain a support of the wires on the side of the thread, the sets and frames are available with calibrated wires of different sizes. The pitch and type of thread determine the choice of the correct calibrated wires. Using a wire other than those indicated and suggested, compromises the exact measurement of the average diameter.
Below we highlight a table for the correct purchase of the calibrated wires to be purchased based on the size, type and pitch of the thread.