Hand-held rotary rock drills used in quarry
operations may be the dry drill, the blower drill, or the
The dry drill allows very little air to pass through
the drill steel while drilling; therefore, you should drill
30 seconds and blow 60 seconds. When the hammer is
not running, the dry drill allows enough air to pass
through for cuttings to be blown out of the hole. Drill
steels for this drill comes in lengths of 2, 4, and 6 feet
with tips made of carbon inserts, diamond, or star.
The blower drill allows a steady supply of air to
pass through the drill steel to help remove cuttings from
the hole while the hammer is running. This type also
permits air to pass through ths drill steel when the
hammer is not running.
The wet drill provides a constant supply of water
through the drill steel while the hammer is running.
Most rock drill failures and complaints result from
Correct lubrication of rock drills
depends on the following:
1. Selection of the proper lubricant
2. Application of enough lubricant for all working
The lubricant must have the correct viscosity for a
uniform rate of feed under many temperatures. Besides
being just viscous (thick) enough, a good rock drill oil
must have the following:
High-film strength and the ability to withstand
Not blow readily, or interfere with valve
Not fog, or exhaust toxic gases.
Not corrode under any operating condition.
Lubricate perfectly at maximum drill speed, at
both high and low temperatures.
Not form gummy leftovers with either hot or
An in-line oiler must be used with each drill. Drill
manufacturers recommend installing the in-line oiler
within 10 to 12 feet from the drill. If the oiler is too far
from the drill, oil droplets tend to gather on the inside of
the hose. This condition results in sporadic delivery of
oil to the drill and can result in serious damage to the
Before operating the drill, ensure the drill steel and
bits are in good condition. Drill steel center holes should
be clear and the shanks should be flat and square, not
chipped or rounded off. Rock bits should be sharp. Dull
rock bits are hard on the drill and the operator. To avoid
injury to yourself and fellow workers, operate the drill
. NEVER pound on stuck steel.
achieved, and you may damage the drill and bit.
l NEVER retract the steel at full throttle. This may
damage the front head parts.
. NEVER strike the drill with teds. This may dent
the cylinder or cause other damage.
l NEVER drag a drill along the ground, because
the exhaust ports and other openings may scoop up dirt
that will cause trouble and possible failure.
. Blow out the air supply hose and flush out the
water hose before connecting it to the drill to rid the line
l Ensure the drill is well-lubricated. Adjust the
in-line oiler, so the steel shank always shows a film of
l Keep the drill aligned with the drill steel and hole.
Hold the drill firmly and apply even pressure with both
. Keep all hands off the trigger or throttle until
ready to start drilling operations.
l When drilling, keep your balance and NEVER
get your face close to the drill.
. Wear safety shoes, safety glasses or impact
goggles, gloves, hearing protection, and a hard hat.
. NEVER rest an air tool on the toes of your boots.
. NEVER point a drill at another person or start an
air drill while it is laying on the ground.
. Do NOT use your body to control an active drill
and never point an air hose at yourself or others.
. Always bleed the airline before removing it from