Snips and shears are used for cutting sheet metal and steel of various thickness and shapes. Normally, the heavier or thicker materials are cut by shears. One of the handiest tools for cutting light (up to 0.064 inch thick) sheet metal is the hand snip (tin snips). The straight snips, shown in figure 13-8, have blades that are straight and cutting edges that are sharpened to an 85-degree angle. Snips like this can be obtained in different sizes ranging from the small 6-inch to the large 14-inch snip. Tin snips will also work on slightly heavier gauges of soft metals, such as aluminum alloys.

It is hard to cut circles or small arcs with straight snips. There are snips especially designed for circular cutting. An example is the aviation snips that are available in a left-hand and right-hand cutting design. To cut large holes in the lighter gauges of sheet metal, start the cut by punching or otherwise making a hole in the center of the area to be cut out. With aviation snips, make a spiral cut from the starting hole out toward the scribed circle, and continue cutting until the scrap falls away.

This part of the chapter is devoted to the common types of air-driven power tools that you will use on a routine basis. You should pay attention to the safety procedures, general operating procedures, and care of these tools.

Figure 13-8-Types of cutting toots.

Figure 13-9.-Rivet-head shaver.