The rack and pinion system chucks have gear backlash, and the grip is weak.
The lever “knuckle” chuck has little backlash. In addition, as a result of the knuckle having more leverage by being twice as long as the rack and pinion style, the grip is stronger.
O.T. Chuck
The 180° turn nut chuck and the opening of the bolt chuck come together to form a hybrid chuck known as the O.T. chuck (“open turn”). Compared to the conventional, universal chuck, the OT chuck is simple and strong.
Because it is a cassette-type, it can be placed in any forging station.
Because the finger lever closes at the knuckle by three fulcrum pins, compared to a conventional chuck, it can securely grip the blanks, and unstable transport is significantly reduced.