Burnishing is a finishing process for bearing pivots and their shoulders of watch and instrument gears. The workpiece lies with its two pivots which are to be burnished, in profiled notches of tungsten carbide flanges and is driven by a carrier in the correct rotational direction.
By means of two rotating, lapped, tungsten carbide discs, the machining process takes place, creating a burnished surface finish. The amount of stock removed depends on the size of the pivot diameter is between 0.005 and 0.01 mm and attains a surface finish of Ra 0,1 und 0,3 ?m (N3, N4). When using ceramic or degussit discs the machining method becomes a pure grinding process reaching greater stock removal.