The following paragraphs are devoted to the
identification general operating practices, and care of
these tools.
DRILLS
The portable electric drill (fig. 1-62) is probably
the most frequently used power tool in the Navy.
Although it is especially designed for drilling holes,
by adding various accessories you can adapt it for
different jobs. Sanding, sawing, buffing, polishing,
screw driving, wire brushing, and paint mixing are
examples of possible uses.
Portable electric drills commonly used in the Navy
have capacities for drilling holes in steel from
1/16 inch up to 1 inch in diameter. The sizes of
portable electric drills are classified by the maximum
size straight shank drill it will hold. That is, a
l/4-inch electric drill will hold a straight shank drill
bit up to and including 1/4 inch in diameter.
The revolutions per minute (rpm) and power the
drill will deliver are most important when choosing a
drill for a job. You will find that the speed of the
drill motor decreases with an increase in size,
primarily because the larger units are designed to turn
larger cutting tools or to drill in heavy materials, and
both of these factors require slower speed.
If you are going to do heavy work, such as
drilling in masonry or steel, then you would probably
need to use a drill with a 3/8- or 1/2-inch capacity.
If most of your drilling will be forming holes in wood
Figure 1-62.-1/4-inch portable electric drill.
or small holes in sheet metal, then a l/4-inch drill will
probably be adequate.
The chuck is the clamping device into which the
drill bit is inserted. Nearly all electric drills are
equipped with a three-jaw chuck. Some drills have a
hand-type chuck that you tighten or loosen by hand,
but most of the drills used in the Navy have gear-type,
three-jaw chucks, which are tightened and loosened by
a chuck key, shown in figure 1-63. Do not apply
further pressure with pliers or wrenches after you hand
tighten the chuck with the chuck key.
Always remove the key IMMEDIATELY after
you use it. Otherwise the key will fly loose when the
drill motor is started and may cause serious injury to
you or one of your shipmates. The chuck key is
generally taped on the cord of the drill; but if it is not,
make sure you put it in a safe place where it will not
get lost.
All portable electric drills used in the Navy have
controls similar to the ones shown on the l/4-inch
drill in figure 1-62.
This drill has a momentary
contact trigger switch located in the handle. The
switch is squeezed to start the electric drill and
released to stop it.
The trigger latch is a button in the bottom of the
drill handle. It is pushed in while the switch trigger
is held down to lock the trigger switch in the ON
position. The trigger latch is released by squeezing
and then releasing the switch trigger.
DISK SANDER
Electric disk sanders (fig. 1-64) are especially
useful on work where a large amount of material is to
be removed quickly, such as in scaling surfaces in
Figure 1-63.-Three-jaw chuck and chuck key.
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