ELECTRICAL POWER TOOLS
General. The power tools described within this
chapter are of the common types used to accomplish
jobs in an efficient manner with less time involved.
These tools are usually used in a shop environment,
although they can be used in the field with an adequate
Electric drills are not to be used on aircraft due to spark
Safety. The following safety precautions will be
followed when operating electric power tools:
Never operate power tools unless they are
completely understood. When in doubt, consult the
applicable operator's manual.
Inspect all power tools before use to ensure
their serviceable condition.
Prior to connecting the tool to its power source,
ensure that the power switch is in the OFF position.
Keep all safety guards in position and wear
safety shields or goggles when necessary.
Fasten all loose clothing and aprons.
Never try to clear jammed machinery before
disconnecting the tool from its power source.
Before plugging a tool into a power source,
ensure that the power source provides the correct
required by the tool.
If the power cord has a ground pin as shown in
figure 6-1, do not attempt to use it with an adapter. The
ground pin serves to decrease the possibility of electric
Do not use sparking electric tools in places
where flammable gases or liquids or exposed explosives
are present. Use pneumatic tools in these areas.
Figure 6-1. Three-Prong Grounded Plug
Ensure that power cables are cared for
according to the following precautions:
Do not allow power cords to come in
contact with sharp objects, oil, grease, chemicals, or hot
Replace cords when they are damaged.
Ensure that the power cord is of sufficient
length so that it will not be pulled taut to reach the work
Position power cords so that they will not
be tripping hazards.
Electric Drills. The electric drill is a hand tool
driven by a small, high-speed electric motor. The motor
is geared to the chuck through reduction gears. The
components of the drill are enclosed in a metal or plastic
pistol grip case to permit ease of handling. Although it
is specially designed for drilling holes, it can be adapted
for different jobs by the addition of various accessories.
It can be used for sanding, buffing, polishing, wire
brushing, and paint mixing. Typical electric drills are
shown in figure 6-2.
Sizes. The sizes of electric drills are classified
by the largest straight shank drills that they will hold.
Therefore, a 1/4 inch drill will hold straight shank drills
up to and including 1/4 inch, and a 3/8 inch drill will hold
bits up to and including 3/8 inch.
Speed. The drill is made to run at speeds which
will prevent the motor from burning out. For this reason,
large drills run at slower speeds than smaller drills. This
is because larger drills are designed to turn larger