Sure-Grip® Power Chuck

Sure-Grip ® Power Chuck Safety and Technical Manual B-87Z
Hardinge ® Sure-Grip ® Power Chuck Gripping Force Illustration
and Parameter Definitions
Fs = Cutting force on turning style cutting tools
Fp = Radial force – passive
Fv = Feed force on turning style cutting tools
Fsp = Required total gripping force (without considering
Z
the effects of angular speed)
Fc = Centrifugal force of the jaws
Fsp = Total initial gripping force with stationary chuck
Q
Lz = Distance between machining and clamping points
dSP dZ Lsp
= Chuck diameter
= Machining diameter
= Chucking length
The information contained in this chapter is presented to help you determine the required gripping force for your
Sure-Grip Power Chuck and the operating forces of the actuating cylinder.
NOTE: All charts in this manual are based on calculated values for the forces, not actual (dynamic) values of the forces.
The following parameters must be calculated:
1. Gripping Force "Fsp Z" required for the machining operation.
(No allowance for the effects of angular velocity)
2. Initial Gripping Force "Fsp Q" required with a stationary spindle with consideration taken for the centrifugal forces
of the chuck jaws.
3. Actuating Cylinder Force (Draw Bar Force) required to provide the initial gripping force "Fsp Q".
Today’s machining techniques require high spindle speeds, and many times, fast cutting feed rates. Because of these
changes it is necessary to consider the safe operation of chucks at these speeds and feeds. Therefore you must be able to
determine the necessary gripping forces required and how they change with the increase or decrease of the spindle speed
(RPM) and the cutting forces applied to the workpiece.
Hardinge Inc. One Hardinge Drive, Elmira, New York U.S.A. 14902-1507 800.843.8801 www.hardingetooling.com
100
Fp