What is Shearing ?

Shearing is a metal fabricating process used to cut straight lines on flat metal stock. During the shearing process, an upper blade and a lower blade are forced past each other with the space between them determined by a required offset. Normally, one of the blades remains stationary.

The shearing process characteristics include:

• Its ability to make straight-line cuts on flat sheet stock
• Metal placement between an upper and lower shear blades
• Its trademark production of burred and slightly deformed metal edges
• Its ability to cut relatively small lengths of material at any time since the shearing blades can be mounted at an angle to reduce the necessary shearing force required.

The illustration that follows provides a two-dimensional look at a typical metal shearing process. Note how the upper shear blade fractures the metal workpiece held in place by the workholding devices. The sheared piece drops away.

Typically, the upper shear blade is mounted at an angle to the lower blade that is normally mounted horizontally. The shearing process performs only fundamental straight-line cutting but any geometrical shape with a straight line cut can usually be produced on a shear.

Metal shearing can be performed on sheet, strip, bar, plate, and even angle stock. Bar and angle materials can only be cut to length. However, many shapes can be produced by shearing sheet and plate.

Materials that are commonly sheared include:

• Aluminum
• Brass
• Bronze
• Mild steel
• Stainless steel

The shearing process uses three types of tool systems. They are used for shearing:

1. Sheet metal and plate using a squaring or bow tie shear
2. Angle materials using and angle shear, and
3. Bar stock using a bar shear.