Snips and Shears
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
Figure 13-8.Types of cutting toots.