To complete finishing of bevel gears, DEMM has the capability to perform running-in. This is carried out by engaging together (coupling) a pinion and a crown adding a fluid containing abrasive. Doing this, minor deformations of the heat treatment are corrected, positioning the contact in the position desired by the customer, and operating noise is reduced. This operation is a sort of "union": the pinion and crown that have meshed together are tested on a Gleason tester and identified with the same coupling number to be rigorously assembled together.
DEMM is equipped with a "lapper" for running-in and a tester for subsequent checks.