TO TRUE

To true consists in obtaining a flat and regular surface by removing excess material. In watchmaking and in Micromechanics, truing is a roughing and finishing operation that prepares a part before the following machining operations: the face of a Main plate, the end of an Axis or the Flank of a Bridge is trued to obtain a flat reference, guaranteeing the accuracy of subsequent dimensions. This operation is performed on a Lathe (transverse truing, the tool moving perpendicular to the Axis of rotation), with a Milling cutter, with a File or on a plate to true accompanied by an Abrasive. The truing of a grinding wheel, a related operation, aims to refresh and make concentric the active surface of the abrasive tool. A properly trued surface determines the flatness, parallelism and quality of the bearings, essential elements for the proper functioning and the Assembly of a Movement. Truing, focused on flatness, is distinguished from Polishing, focused on surface finish and shine.