Use screws of reputed make only. (Eg. TVS, Unbrako). Length of the screw should be as per GMT standards. Write to firstname.lastname@example.org for a free electronic copy of GMT PHNC Instruction Manual.
SCREW SIZE TIGHTENING TORQUE
M8 39 Nm
M10 77 Nm
M12 110 Nm
M16 220 Nm
M 20 400 Nm
If you use screws that are longer than recommended size, the top jaw will not clamp with master jaw, as the clamping screw will rest at the bottom face of master jaw T-Slot. This will result in master jaw breakage.If the soft-jaws are purchased from outside source, ensure that the jaws meet GMT standards.
Click here for further information and instructions on chuck maintenance. or visit our website www.gmt.co.in