The masters are samples used for zero-setting measuring instruments (with electronic sensors or dial gauges).
Usually their shape reproduces the manufactured article.
They are made with materials and treatments that guarantee reliability and stability and with very accurate machining tolerances.

The master gears with involute profile, cylindrical and helical, used for the “rollers dimension” check or the rolling check, fall in this range of products.

For further information please consult the page on masters and master gears in the MG site.