Select a letter above to see the terms listed in MMS Online's Workholding Glossary

Arbor
A workholding device that locates or grips on an internal diameter or feature.
    »To see Arbor suppliers click here.

B - There are no Terms for this section

Center(s)
A device that supports a workpiece on a common axis by one or two ends.
    »Note: A center that rotates is called a live center, one that does not rotate is called a dead center.

Centrifugal Force
The force generated by rotation that tends to move all rotating parts away radially from the axis of rotation.

Chucks
Universal holding devices capable of OD and/or ID clamping. A chuck may be actuated manually, pneumatically, hydraulically or electrically.
    »Note: Click here for a document defining Types of Chucks.

Chuck Adapter
The interface between the machine and the chuck. It can be a separate component or integral to the chuck body.

Chuck Body
The part of the chuck that encloses the operating mechanism for actuating the movable jaw(s).
    »Note: Click here for a document defining Types of Chucks.

Clamping Cylinder (Actuator)
A device that actuates the chuck through the aid of pneumatic or hydraulic energy.

Clamping Force
The algebraic sum of the individual radial forces applied by the top jaws on the workpiece - see Top Jaw

Clamping Torque
The product of the clamping force, clamping radius and the coefficient of friction between the top jaws) and the workpiece.

Collet
A split sleeve which when expanded or contracted, grips the workpiece.
    »To see Collet suppliers click here.

Dead Length
The action of gripping a workpiece without changing its axial position.

Dynamic Clamping Force
The actual clamping force when the workholding device is rotating.

Expanding Mandrel - see Arbor

Face Driver
A unit having part driving chisels that penetrate the part face of a workpiece when pressure is applied.

Fixture
A device used to locate or support material, workpiece(s), or tool(s) during machining operations. Usually custom designed to hold a specific workpiece.

G - There are no Terms for this section

Hard Jaws
Top Jaws that are made to final size of hardened steel. They are not intended to be machined in use see Top Jaw; see Soft Jaw
    »To see Hard Jaw suppliers click here.

Hysteresis
The change in static clamping force after the chuck has been rotated at working rotational speed with a constant input force - see Input Force

Indicating Band
A diameter on the chuck body designated for measuring runout of a chuck.

Input Force
The force acting on the chuck, applied from an external energy source that actuates the chuck's mechanism.

Input Torque
The torque acting on the chuck, applied from an external energy source that actuates the chuck's mechanism.

J - There are no Terms for this section

K - There are no Terms for this section

L - There are no Terms for this section

Mandrel - solid
Cylindrical or symmetric shaft, sometimes tapered, that locates on an internal diameter or feature of the workpiece.
    »To see Mandrel suppliers click here.

Master Jaw
A radial moving part within the chuck body to which the Top Jaw is mounted.
    »To see Master Jaw suppliers click here.

Maximum Actuating Force
The maximum input force allowed.

Maximum Rotational Speed
The maximum rotational speed in RPM specified by the manufacturer for a chuck with standard jaws in compliance with the manufacturer's instructions.

Maximum Static Clamping
The maximum clamping force obtained when the maximum permissible input force (or maximum input torque) is applied to a particular chuck.

Moment of Inertia
The moment of inertia with respect to a given axis is the limit of the sum of the products of each of the elemental particles in which the body may be conceived to be divided and the square of their distance from the given axis.

N - There are no Terms for this section

O - There are no Terms for this section

Pull Back
The action of gripping a workpiece while simultaneously pulling in an axial direction usually against a fixed locator.

Q - There are no Terms for this section

Rotational Balance
The equilibrium of all masses around the axis of rotation (any difference(s) between the axis of rotation and the center of gravity will cause imbalance).

Soft Jaw
Top Jaw blank that can be machined to specific dimensions that are mounted to a Master Jaw - see Hard Jaw; see Master Jaw (Base Jaw)
    »To see Jaw suppliers click here.

Spindle Liner
A sleeve, which is inserted in a spindle to reduce the internal size.

Static Clamping Force
The clamping force of the chuck when the chuck is not rotating.

Tooling Column
A device used in association with clamping device to hold workpiece in position (horizontal or vertical).

Top Jaw
The component that clamps the workpiece and is mounted on a Master Jaw.
    »To see Jaw suppliers click here.

U - There are no Terms for this section

V-block
A positioning device.

Vise
A stationary workholding device having one or more moveable jaws that is used to clamp a workpiece.
    »To see Vise suppliers click here.

Workholding Chuck
A clamping device with moveable jaws or a collet to hold a workpiece, also defined as "chuck."
    »Note: Click here for a document defining Types of Chucks.

Working Rotational Speed (n_w)
The rotational speed in RPM under machining conditions (n_w<=n_max).

x - There are no Terms for this section

Y - There are no Terms for this section

CHUCK TYPES

Z - There are no Terms for this section