WORK HOLDING DEVICES

WORK-HOLDING DEVICES

In grinding, different work-holding devices are used to keep the work piece in position.
The work-holding devices used in grinding are:

1. Magnetic chuck
2. Vice
3. Angle plates
4. V blocks
5. Clamps

 Magnetic chuck
Magnetic chucks are of two types.

1. Electromagnetic chuck
2. Permanent magnetic chuck and they are specified by the length and width.

The magnetic power of the electromagnetic chuck can be varied according to the size of the work. But not so in the case of a permanent magnetic chuck.

Uses
The magnetic chuck (Fig 1) is the most commonly used work-holding device. It holds ferrous work pieces. A ferrous work-holding device also can be mounted on it

Vices
Vices are used to hold jobs with narrow surface or non-ferrous work pieces, which cannot be conveniently held on magnetic chucks.
A vice may be set on the grinder table directly or on the magnetic chuck.
Vices are of 3 types.
A PLAIN vice (Fig 2) is used to hold work pieces for plain or step grinding

A TILTING TYPE vice (Fig 3) is used to hold the work piece while grinding angular surfaces. If required, the tilting base can be removed and can be mounted on the magnetic chuck as a plain vice

A UNIVERSAL vice (Fig 4) is used to hold the work Piece while grinding the angular surface in two different planes. This is small in size. So it is mainly used in tool grinding

Angle plate
Angle plates are used to hold the work piece while grinding, one surface perpendicular to another surface (plain type, Fig 5) or while grinding one surface at an angle to another surface (adjustable type, Fig 6).

‘V’ block
'V blocks are used to hold the round work pieces while, grinding a flat on the work piece. V block (Fig 7)
These are used for holding tube or bar work pieces for grinding flat surfaces on the exterior. Square work pieces may also be supported in Vee blocks for grinding the external corners of the work.
Vee blocks may be attached to the work table by clamps or be set on a magnetic chuck
Magnetic Vee blocks can be used also in combination with other mounting devices, such as angle plates which themselves can be clamped to the work table or held in position on a magnetic chuck.

Clamps (Fig 8)
Clamps are used to hold any work piece or a work-holding device on the table. Alternatively they may be held on a magnetic chuck.

De-magnetizer
It is a special device used to remove the magnetic power from an object. In grinding whenever a job is ground by holding it on the magnetic chuck, the job will also get some magnetic power. A de-magnetizer is, therefore, used to remove this.