AUGERS

Earth augers may use continuous-flight augers (fig. 14-6) or single-flight augers (fig. 14-7).

The auger head is attached to the drill shank by a square-drive pin connector. Continuous-flight augers usually come in sizes from 5 to 12 inches in diameter and various lengths. A 5-inch auger can drill about 100

Figure 14-7.-Single-flight auger.

feet in suitable material; a 10-inch auger is limited to about 40 feet.

Single-flight augers, lifted after every 8 to 10 inches of penetration to clear the cuttings, measure from 14 to 36 inches in diameter. Single-flight augers are limited to depths of about 15 feet.

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.