Q31.
List the safety precautions that apply to
power tools.
Q32.
List the safety precautions that apply to
extension cords.
PORTABLE PNEUMATIC POWER
TOOLS
LEARNING OBJECTIVES: Identify dif-
ferent types of portable pneumatic power tools.
Describe the uses of different types of portable
pneumatic power tools. List the safety
precautions that apply to portable pneumatic
power tools.
Portable pneumatic power tools are tools that look
much the same as electric power tools but use the
energy of compressed air instead of electricity. Because
of the limited outlets for compressed air aboard ship
and shore stations, the use of pneumatic power tools is
not as widespread as electric tools. Portable pneumatic
tools are used most around a shop where compressed
air outlets are readily accessible.
PNEUMATIC CHIPPING HAMMER
The pneumatic chipping hammer (fig. 1-64)
consists basically of a steel piston that is reciprocated
(moved backward and forward alternately) in a steel
barrel by compressed air. On its forward stroke the
piston strikes the end of the chisel, which is a sliding fit
in a nozzle pressed into the barrel. The rearward stroke
is cushioned by compressed air to prevent any
metal-to-metal contact. Reciprocation of the piston is
automatically controlled by a valve located on the rear
end of the barrel. Located on the rear end of the barrel is
a grip handle, containing a throttle valve.
The pneumatic hammer may be used for beveling;
caulking or beading operations; and for drilling in
brick, concrete, and other masonry.
Chipping hammers should not be operated without
safety goggles, and all other persons in the immediate
vicinity of the work should wear goggles.
While working, never point the chipping hammer
in such a direction that other personnel might be struck
by an accidentally ejected tool. When chipping alloy
steel or doing other heavy work, it is helpful to dip the
tool in engine lubricating oil about every 6 inches of the
cut and make sure the cutting edge of the tool is sharp
and clean. This will allow faster and easier cutting and
will reduce the possibility of the tool breaking.
When nearing the end of a cut, ease off on the
throttle lever to reduce the intensity of the blows. This
will avoid any possibility of the chip or tool flying.
If for any reason you have to lay the chipping
hammer down, always remove the attachment tool from
the
nozzle.
Should
the
chipping
hammer
be
accidentally started when the tool is free, the blow of
the piston will drive the tool out of the nozzle with great
force and may damage equipment or injure personnel.
ROTARY AND NEEDLE IMPACT
SCALERS
Rotary and needle scalers (figs. 1-65 and 1-66) are
used to remove rust, scale, and old paint from metallic
and masonry surfaces. You must be especially careful
when using these tools since they will "chew" up
anything in their path. Avoid getting the power line or
any part of your body in their way.
The rotary scaling and chipping tool, sometimes
called a "jitterbug," has a bundle of cutters or chippers
for scaling or chipping (fig. 1-65). In use, the tool is
pushed along the surface to be scaled, and the rotating
chippers do the work. Replacement bundles of cutters
are available when the old ones are worn.
1-40
Figure 1-64.—Pneumatic chipping hammer.
Figure 1-65.—Rotary impact scaler.
