Metric thread M12 mm and pitch 1.25 mm. Combined.
The tool is used for cutting internal threads - manually or mechanically. It consists of a working part and a tail. The workpiece of the roller includes a cutting part (which cuts the thread) and a calibrator that cleans the thread and guides the roller to the end of the cut. The tail is used to attach the roller to a cartridge or a turret. To cut an internal thread, first drill the element on which the thread is to be made with a drill, the number of which is selected by table, then a cut-out is made to facilitate the holding of the drill in the hole, then the actual Cutting the thread. Initially, the screwdriving is done by hand, once it engages the roller, rotates clockwise one or one-half turn and returns a quarter or a half turn back to remove the chips. During operation, the brush must be lubricated with oil, malleable cast iron, and plastics are cut without lubrication.