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The squaring shear performs three distinctly different operations: 

1. Cutting to a line 

2. Squaring 

3. Multiple cutting to a specific size 

When cutting to a line, place the sheet on the bed of the shears in front of the cutting blade with the cutting line even with the cutting edge of the bed. To cut the sheet with a foot shear, step on the treadle while holding the sheet securely in place. 

Squaring requires several steps. First, one end of the sheet is squared with an edge (the squaring fence is usually used on the edge). Then, the remaining edges are squared by holding one squared end of the sheet against the squaring fence and making the cut, one edge at a time, until all edges have been squared. 

When several pieces must be cut to the same dimensions, use the backstop, located on the back of the cutting edge on most squaring shears. The supporting rods are graduated in fractions of an inch and the gauge bar may be set at any point on the rods. Set the gauge bar the desired distance from the cutting blade of the shears and push each piece to be cut against the gauge bar. All the pieces can then be cut to the same dimensions without measuring and marking each one separately. 

Foot-operated shears have a maximum metal cutting capacity of 0.063 inch of aluminum alloy. Use powered squaring shears for cutting thicker metals. [Figure 4-24] 

## Throatless Shear 

Airframe technicians use the throatless shear to cut aluminum sheets up to 0.063 inches. This shear takes its name from the fact that metal can be freely moved around the cutting blade during cutting because the shear lacks a “throat” down which 

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metal must be fed. [Figure 4-25]  This feature allows great flexibility in what shapes can be cut because the metal can be turned to any angle for straight, curved, and irregular cuts. Also, a sheet of any length can be cut. 

A hand lever operates the cutting blade which is the top blade. Throatless shears made by the Beverly Shear Manufacturing Corporation, called Beverly$^{TM}$ shears, are often used. 

## Scroll Shears 

Scroll shears are used for cutting irregular lines on the inside of a sheet without cutting through to the edge. [Figure 4-26] The upper cutting blade is stationary while the lower blade is movable. A handle connected to the lower blade operates the machine. 

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