Various sizes of auger heads (fig. 14-8) are available
for different job specifications. Most of them feature an
advance center or pilot cutter that helps keep the drill
hole alignment straight and makes the cutting easier for
the larger auger head. As shown in figure 14-9, the head
should be slightly larger than the auger flights, so it will
not bind or stick in the hole.
These heads can also be made of different materials
to meet unlike soil conditions. Cutting edges and teeth
are usually steel-hardened by various means, such as
tungsten carbide. Worn or broken teeth may be built up
by hardfacing. These teeth are sometimes called fingers
and are generally detachable or reversible.
Figure 14-8.Auger boring heads.
Figure 14-9.Auger boring head nomenclature.
DRILLING
Drilling resistance or control of the rate of feed
prevents the threads from penetrating in proportion to
their turning speed. Material, cut by the bit, is gripped
by the threads and forced out of the hole by the screw
conveyor action.
The flights are made in sections
proportional to the feed length of the drill unit and are
connected to each other by bolting or pinning.
SAFETY
A few safety precautions when operating an auger
are as follows:
l Obtain a digging permit before drilling or boring.
. Have all underground utilities and obstructions
marked and identified.
. When traveling with the auger truck, make sure
all attachments are secured properly.
l Always sound the horn and use a backing guide
when backing the auger.
l Do NOT travel with an auger bit attached to the
drill shank. This practice can result in destruction of the
drill shank inner seals.
. Do NOT allow personnel to stand near the auger
when boring holes.
. Do NOT allow personnel to stand near the auger
when swinging or moving the auger boom.
. Do NOT exceed the capacity of the auger when
pulling or setting poles.
. Do NOT try to remove any objects from the auger
when the auger is running.
. When boring into material of unknown
consistency, run the unit at low speed.
. Always protect personnel from open holes by
placing caution tape and covers around and over the
holes, and illuminate the area with lighting at night.
AIR COMPRESSORS
A compressor is a machine that compresses air from
an initial intake pressure to a higher exhaust pressure
through a reduction in volume. A compressor consists
of a power source, a compressor unit, and accessory
equipment. A gasoline or diesel engine provides power
to operate the compressor. Most compressors, used in
14-7