Sheet Metal Shears

Very common types of sheet metal shear are the bench shears (also known as a lever shears). These types of machines are smaller than some of the other types of sheet metal shears. Like most other types of shears these machines are designed to increase the leverage of the cutting process. Mostly used for rough cutting small to medium pieces of sheet stock with gauges up to about .12". The actual abilities of the bench shear will depend on the specification from the manufacturer.

Another common type of sheet metal shear is the guillotine shear. Some people refer to these types of machines as power shears or squaring shears. Most of these types of machines are foot powered by the operator but there are some that are made to be hand operated. These use two separate blades to make the cuts. A stationery blade and a moveable blade. The movable blade moves down and then across the fixed stationary blade to complete the cut.

A nice feature with the guillotine shear is that on some models the moving blade can be set at an angle (known as the shear angle). Using a shear angle reduces the amount of force needed to cut through the metal. For example, you can reduce the amount of force needed to make the cut by 20% by setting the shear angle at only 5 degrees. The amount of force to make the cut is less but the stroke length increases. From a physics stand point the amount of energy to make the cut is the same but from an operators stand point the amount of work seems to be a lot less.

For sheet metal shears, the cutting blades are not sharpened. They are in fact square edged. The reason for this is that you need strength in order to cut metal and a sharpened edge is simply not that strong. Most shears can cut a variety of metals like aluminum, bronze, brass, sheet metal and even mild steel.

For large and/or repetitive cutting power sheet metal shears are a possibility. Power shears are great when there is a large area needing to be cut. These shears are pneumatically powered and as a result are fairly light weight. Although designed to primarily make straight cuts, they can be used to make slow bending curves also. 

Metal bandsaws can also be used but there are limits to the size of the sheet stock a metal bandsaw can cut. Using power sheet metal shears provides a lot more flexibility for the operator.

The last type of sheet metal shears to be discussed is known as the throatless shear. Throatless shears provide endless possibilities to the cutting process because as the name implies, there is no 'throat' that the sheet metal must be fed into. In a throatless shear the operator can actually move the metal to be cut completely around the part of the throatless shear that is doing the cutting. These type of sheet metal shears allow the operator to make very complex curved cuts in addition to being able to make straight line cuts too.