CNC lathe chuckGMT CNC Lathe Chuck rotates at high speeds, suitable for modern turning centres. Power Operated Three Jaw Chuck with Through Bore (PHNC) is one of India’s largest selling and most trust chucks for CNC Lathes and turning centres.


Standard sizes available (3 jaw) 135mm, 165mm, 200mm, 250mm, 315mm, 400mm and 500mm
2 Jaw and 4 Jaw chucks with through bore is available on request.

Power Operated Three Jaw Chuck with Through Bore (PHNC) :

GMT Power Operated Hollow High Speed Chucks rotates at high speeds on CNC lathes. The compact construction of GMT CNC lathe chuck offers 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 weigh less in these chucks. This not only reduces the mass but also lowers the centre of gravity, which make the centrifugal losses low.


Furthermore, 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 has large contact area with the base jaws. The weight of the body, base jaws and hard jaws are less, without sacrificing the other essential criteria. Removal a large extent of material on the chuck body reduces the weight. (from sizes 250 mm to 500 mm). The chuck body is forge steel. The guideways are hardened and  ground.

Besides, the wedge, made of nickel chrome steel. This is case hardened and ground on all the working surfaces. The base jaws also made of nickel chrome steel. The grinding match both the wedge and the body guideways. The base jaws are guided in the deep, wide, hardened slots in the body. Consequently, these provide the ample bearing area necessary to withstand the forces resulting from high gripping action.

There is a provision for manual lubrication of sliding surfaces through grease nipples. 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 grip a wide range of diameters. Finally, hardened chrome case hardened and ground base jaws and the wedge ensure high load carrying capacity over a very long period.

cnc lathe chuck performance detail

cnc lathe chuck specification drawing

cnc lathe chuck specification

cnc lathe chuck-jaw-drawing

cnc chuck chuck jaw specification chart


  • Hard Jaws are common for PHNC & PHCNC
  • Soft Jaws are supplied as blanks and are common for PHNC & PHCNC
  • *Offered in PHNC only.
  • Only Soft Jaws are available with 2 Jaw Chucks
  • Serration 1.5 x 60o on Base jaws, Hard jaws and Soft jaws are on request.

Power Operated Three Jaw Centrifugally Compensated Chuck (PHCNC) :

Standard power chuck will not work at these speeds because of the tremendous centrifugal force. At these speeds, the chuck 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. Also, the design is such that the clamping force is very near to that of static clamping force, even at very high speeds.

Finally, visit us at – a new blog dedicated to all GMT customers…interact with our technical experts.