[SEL] More Cold Cut Sawing

[Richard Allen]

This reply is another one that is a bit late. 

I have cut corrugated sheet steel using a wide blade wood gouge or
chisel, but not quite how you would think. Sharpen one side of the
chisel like a knife (at a 30° angle) for about an inch (2.5cm) and
leave the other side alone. To cut a piece of sheet steel, start by
driving the corner of the knife-sharpened side into the center of the
metal along the line where it is to be cut. Strike the unsharpened side
of the chisel with a hammer to make it cut and work from the middle to
the outside and then go back to the middle where the cut was started
and do the other half. It won't work nearly as well if you start from
an outside edge and try to work across because if you push on a sheet
metal edge it bends and folds up, so start in the middle so the sheet
metal is under tension from the hammer blows on the chisel. It works
for cutting the tops off of barrels, too. An air chisel works great but
it can be heard five miles away! Ruins your hearing without protection,
too.

For small jobs, like opening a can of chili for lunch, I have also used
a slot type screwdriver instead of a wide wood gouge chisel by
sharpening one side. If you heat the can of chili first, keep a clean
rag over the cut because it sprays chili all over if it is hot and
soupy.

A band hacksaw also works for fast cutting when half dozen or more
sheets needed to be cut. Of course not everybody has a band hacksaw in
their hip pocket that will accommodate sheets 26-5/8 inches (67.6 cm)
wide. For sheet metal segments narrow enough (like roof eves gutters)
to fit in a band hacksaw it works great. Starting and finishing the cut
where the saw blade is in contact with only one or two sheets is a
problem when the attack angle of the blade teeth is not oblique enough
(needs to be about a 5° angle) because the teeth hook on the edge of
one sheet. Once the cut begins and several layers are engaged it saws
like a dream. A cold chisel is handy for finishing a cut, but is not
necessary all the time.

Richard Allen