Created by Gary W. Adams,
Canyon Lake High School
Chapter 9

The portable electric drill is used to
pierce metal, wood, plastics, and other
materials.

The size of the portable drill is
determined by the largest diameter drill
shank that can be inserted into the
chuck.

The most common chuck sizes are 1/4”,
3/8” and 1/2”. Portable drills can be
selected according to size, motor rating,
whether or not reversible, single or
variable speed, and type of use
Pre-Use Check

Thoroughly review and understand
information provided in the portable
power drill operator’s manual with
particular attention given to descriptions
of safety procedures.

Before using, always inspect the
portable power drill for damage or
disrepair. In addition, assure the drill
chuck is functioning properly and as
appropriate, inspect the electrical cord
and plug or battery/battery pack

If the portable power drill fails your
inspection, notify your supervisor and
remove the portable power drill from
service by attaching a red tag that states
“DO NOT USE.” Complete red tag with
appropriate information.
Procedure for Safely Operating
the Portable Drill

Use only sharp twist drills; disconnect
the power source when changing twist
drills.

Tighten the chuck securely and remove
the chuck key.

Use a center punch or awl to locate the
center of the proposed hole.

Secure the stock, be sure the drill is
properly grounded or double insulated,
and that the cord is clear of the work
area.

Hold the drill with both hands at the
correct angle while applying a steady,
even pressure. Be sure you have good
footing and a firm grip. Never attempt to
drill work held in your hand.

Withdraw the drill occasionally to clear
the cuttings or chips.

Apply a coolant or lubricant when drilling
metal

Ease off the pressure as the twist drill
cuts through the stock to prevent
splintering or grabbing.

Scrap stock can be clamped to the
backside of the material being drilled to
prevent splintering and grabbing.

Note: When drilling large diameter
holes, it may be necessary to first drill a
pilot hole.

Never wear a tie or loose clothing or
jewelry when using a portable power
drill. Tie long hair back or secure under
a cap.

Always wear safety glasses or goggles
when drilling.

Do not operate a portable power drill in
the presence of flammable fumes.

Avoid using a portable electric drill when
it is raining or in wet conditions.

Use the correct drill bit for the type of
material to be drilled and task at hand.

Before inserting a battery or plugging in
a portable power drill, turn the power
switch off.

Make all portable power drill
adjustments with the power switch off
and the drill unplugged.

Insert bit into drill chuck and tighten with
the chuck key. Remove chuck key from
the drill chuck before starting the
portable power drill.

Keep your hands and fingers away from
the rotating drill chuck and bit.

Do not force a drill bit against the stock
being drilled. If a drill bit is not
penetrating properly, turn the drill off and
change the drill bit.

Use caution when changing drill bits, as
they are sharp and can become hot
during use.

Only recharge a portable power drill
battery or battery pack with a battery
charger recommended by the
manufacturer.

Always use the type of battery or battery
pack specified for the portable power
drill.

Never carry a portable power drill by the
power cord.

When carrying a portable power drill,
turn the drill off and keep your index
finger away from the power switch.

Never stop the rotation of the drill chuck
or bit with your hands or fingers.

Always clean your work area upon
completion of the drilling task.
Drilling Metal

Determine the center of the hole and
mark it with a center punch to keep the
drill from crawling.

Clamp small stock in a drill press vise
(general purpose, angle, rotary indexing
table, or universal compound vise). A strap
clamp for flat stock and V-block for round
material are recommended for small stock.
V-blocks are sometimes used with Yclamps. C-clamps and angle iron also
make good stock supports, especially if the
metal is irregular in shape. Parallels and
strap clamps are fastened to the table with
special fasteners.

Use a good grade of cutting oil while
drilling. It cools cutting lips and stock,
lubricates chips, improves the finish of
holes, and lengthens the life of drills.
Kerosene can be used on dense
aluminums. Some nonferrous metals are
drilled without the use of oil.

Drilling metal is similar to drilling wood in
that a steady; even pressure is applied
until the bit begins to break through the
metal when drilling holes. Most ferrous
metals will produce ribbons or rolled
chips, instead of small chips, if proper
pressure is applied. Chips will appear
when drilling cast iron. Use a brush to
remove these chips from the table, not
your fingers.
Other Drill Press Operations

Reaming and Lapping - Reaming is the
removing of a small amount of metal to
increase the size of an existing hole.
Lapping a surface is done with a rod and
abrasive. It is more like polishing than
cutting metal.

Plastic and Glass Drilling - Special bits
are used to drill both plastic and glass.
Plastic holes should be slightly oversize.
Glass is drilled with either a diamond-tip
or tungsten carbide tipped bit. Glass is
placed on a flat surface and the proper
amount of pressure is applied, and
kerosene, water, or turpentine is used as
a lubricant while drilling.

Metal Finishing and Shaping - There are
several different types of shaping, deburring, and grinding points used to
shape metal. Cutters and grinders are
used to shape metal, plastic, and wood.
The quill is locked at the proper height,
and the stock is pushed against the
cutter or grinder lightly. The quill is also
locked in the proper position when using
wire brushes or buffers.
Drill Motor Parts
Drill Motor Types
Chuck Key
Chuck
Keyless Chucks
Twist Drill Bits
Step Bits
Twist bit With Pilot Point
Wood Auger Bit
Glass Bit
Mason bit
Round Shanks
Taper Shank
Off Set Shank
Brace with bits
Pre Test

Sleeves should be rolled up; ties,
watches and rings should be removed;
and safety glasses should be worn while
operating the electric drill.
 True

Be sure the drill is double insulated or
safetly grounded before operating it.
 True

Never operate the portable drill while
standing in water or on wet floor.
 True

Use the forefinger to brush chips from
around the twist drill bit.
 False

Always lock the switch in the on position
when using the portable drill.
 False

The twist drill will not run turn if the
chuck is not properly tightened.
 False

Stock should be securely fastened to
prevent twisting during the drilling
process.
 True

The drill should be pulled across the
floor by the power cord.
 False

The center of the hole to be drilled
should be marked with a center punch
or an awl.
 True

Drill with even, steady pressure and let
the drill to the work
 True

When drilling deep holes withdraw the
drill bit from the hole several times to
clear out the chips.
 True

When using a large drill, brace the body
well to prevent injury
 True

Twist drill are made and sharpened to
cut in a clockwise direction.
 True

Power should be disconnected and the
twist drill(bit) should be removed from
the chuck as soon as the work is
complete.
 True

It is permissible to operate the portable
drill with the chuck key in the chuck.
 False

A twist drill (bit) is designed to cut a hole
in metal not wood, but can be used in
wood.
 True

A true wood bit with a round shank can
be used in a portable drill motor.
 True

A spade bit is not made for a portable
drill motor.
 False

Another name for the geared key chuck
is a 3-jawed Jacob Chuck.
 True

The safety rules apply to all drills even
cordless drill motors.
 True

The big ½ inch chucked drills are larger
and more dangerous because they can
bind or hang up and the motor torque
can break a wrist or forearm easily.
 True

Apply a coolant or lubricant when drilling
metal
 True

Ease off the pressure as the twist drill
cuts through the stock to prevent
splintering or grabbing.
 True

Never wear a ties, loose clothing or
jewelry when using a portable power
drill.
 True

It is considered safe to operate a
portable power drill in the presence of
flammable fumes.
 False

Recharge a portable power drill batteries
with the battery charger recommended
by the manufacturer.
 True

Always use the type of battery or battery
pack specified for the portable power
drill.
 True

Never stop the rotation of the drill chuck
or bit with your hands or fingers.
 True

Use only sharp twist drills; disconnect the
power source when changing twist drills.
 True

Hold the drill with both hands at the correct
angle while applying a steady, even
pressure. Be sure you have good footing
and a firm grip and never attempt to drill
work held in your hand.
 True