GMT - Power Chucks
Standard sizes available (3 jaw) 135mm, 165mm, 200mm, 250mm, 315mm, 400mm and 500mm
2 Jaw and 4 Jaw chucks with through bore can be offered on request
Power Operated Three Jaw Chuck with Through Bore (PHNC) : GMT Power Operated Hollow High Speed Chucks are designed to rotate at high speeds on CNC lathes. The compact construction of the PHNC Power Chucks offer further advantage of less weight and low inertia which have positive influence on the dynamic effect of CNC machine spindle. These power chucks have a large through bore and are therefore suitable for bar work. The base jaws and top jaws weight are reduced in these chucks. This not only reduces the mass but also lowers the centre of gravity, which make the centrifugal losses low.
Power chucks on CNC machines need to deliver high initial gripping force. GMT takes care of this in the design by making the power chuck operate with a large drawbar pull. Consequently, the wedge is designed to have large contact area with the base jaws. The weight of the body, base jaws and hard jaws are less, without the other essential criteria being sacrificed. The chuck body is recessed to remove a large extent of material to reduce the weight. (from sizes 250 mm to 500 mm). The chuck body is forged steel. The guideways are hardened and ground.
The wedge, made of nickel chrome steel, is case hardened and ground on all the working surfaces. The base jaws also made of nickel chrome steel, are case hardened and ground to match both the wedge and the body guideways. The base jaws are guided in the deep, wide, hardened slots in the body, which provide the ample bearing area necessary to withstand the forces resulting from high gripping action.
Provision has been made for manual lubrication of sliding Serrations are ground on the top face of the base. The serrations on the bottom to match the base jaws. The various radii on the hard jaws in conjunction with the serrations are designed to grip a wide range of diameters. hardened chrome case hardened and ground base jaws and the wedge ensure high load carrying capacity over a very long period.
Power Operated Three Jaw Centrifugally Compensated Chuck (PHCNC) : Standard power chuck will not work at these speeds because the tremendous centrifugal force generated at these speeds will tend to loosen the job. More importantly, there will be an abrupt and huge loss in the gripping force of the chuck. When there is a loss in gripping power, it will adversely affect the cutting parameters of the lathe. The design is such that the clamping force is very near to that of static clamping force, even at very high speeds.