Manually operated self-centering chuck equipped with a flat spiral and a through hole. Mainly used on traditional horizontal and vertical lathes, milling machines and rotary tables. All-steel body, designed to ensure optimal accessibility. Reduced weight and level of inertia. High concentricity accuracy up to 0.02. Available in versions with cylindrical connection, short cone connection, Camlock, bayonet. Burnished jaws, ground under preload on the chuck to obtain greater precision. APPLICATION: Clamping of asymmetrical components for turning and milling. EQUIPMENT: Set of claws for inside and outside or set of base claws and reversible inserts operating key and fixing screws