The locking mechanism of piston tool post is to push the holder out against the angle gib ways of dovetail by the center hole piston. Precision ground and hardened on the piston contact surface and the dovetail to ensure rigidity and repetitive accuracy. Advanced design provides positive rigidity to minimize chatter and vibration in turning. Can be quickly and easily installed on an engine, bench or turret lathe for a wide range of operations, from precise work to heavy duty cutting. AXA Piston Type Set Included one of each: Quick Change Tool Post; Turning and Facing Holder #1; Boring Turning and Facing Holder #2; Universal Parting Blade Tool Holder #7; Heavy Duty Boring Bar Holder #4; Knurling Turning & Facing Holder #10. This item is in the category "Business & Industrial\CNC, Metalworking & Manufacturing\Workholding & Toolholding\Toolholding\Quick Change Tool Post". The seller is "zhaom_9034" and is located in this country: US.