C-clamp when necessary. The wood block helps
Saw thin metal as shown in figure 5-30. Notice the
support the blade and produces a smoother cut. Using
long angle at which the blade enters the saw groove
the wood only in back of the metal permits the layout
(kerf). This permits several teeth to be cutting at the
lines to be seen.
same time.
Metal that is too thin to be held, as shown in figure
Hacksaw Safety
5-31, can be placed between blocks of wood, as shown
in figure 5-3 1. The wood provides support for several
The main danger in using hacksaws is injury to
teeth as they are cutting. Without the wood, as shown
your hand if the blade breaks. The blade will break if
in view B of figure 5-31, teeth will be broken due to
too much pressure is applied, when the saw is twisted,
excessive vibration of the stock and because
when the cutting speed is too fast, or when the blade
individual teeth have to absorb the full power of the
becomes loose in the frame. Additionally, if the work
stroke.
is not tight in the vise, it will sometimes slip, twisting
the blade enough to break it.
Cut thin metal with layout lines on the face by
using a piece of wood behind it (fig. 5-32). Hold the
wood and the metal in the jaws of the vise, using a
PORTABLE POWER HANDTOOLS
You will be using portable power drills, hammers,
and grinders in the shop and out on the job. You should
be thoroughly familiar with the operation and care of
these tools and with applicable safety precautions.
Individual electrically powered hand tools are not
covered in this chapter. However, it is important that
you understand some important safety and operating
procedures for these tools. Only the most common
portable pneumatic power tools will be covered in this
Figure 5-30.--Gutting thin metal with a hacksaw.
chapter.
Most portable power tools are driven by
electricity. However, the portable power tools that you
use may be powered by electric motors or by air
(pneumatic) motors. Whether electric powered or air
powered, the tools and the procedures for using them
are basically the same. Maintenance information
about portable power tools can be found in the
equipment owner' s manual.
ELECTRICAL POWER TOOLS
Figure 5-31.--Cutting thin metal between two wooden blocks.
Several safety and operating precautions must be
observed when you use electrical tools. The most
important of these relate to electrical shock. Electrical
tools are made so all current-carrying parts, except
filters, are insulated from housings and handles. The
tools are laboratory tested to ensure they are safe to
use when new. However, tool abuse (overload or
dropping) could cause a short and you could receive
an electrical shock. You can reduce the electrical
shock hazard by ensuring that there is a grounding
wire between the tool housing and a positive ground.
All electrically powered tools must have a
Figure 5-32.--Gutting thin metal using wood block with
three-wire cord and be double-insulated. All
layout lines.
5-18