Drilling

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Always wear safety equipment, including safety glasses or goggles and gloves, when drilling.

1. A special, short-handled hammer called a single jack is used for one-handed drilling. Hammer heads weigh either 3 or 4 pounds, and handles are 10 inches long. The short handle helps you place blows accurately.

Single jack driller at work.

A long-handled single jack, an engineer's hammer with a 14 inch handle and a 3- or 4-pound head, for example, can be' used for two-handed drilling with another worker holding the steel. The proximity of both hands to the steel required by the handle assures that accuracy and safety are not sacrificed. We call this technique modified double jacking.

2. The driller will be kneeling on one or both knees, or sitting. If modified double jacking is used, the holder should position himself across the steel from the driller, and wear gloves on both hands.

Modified double jack drilling team at work.

Assume a comfortable position and change positions and tasks regularly to help minimize stiffness in legs, arms, and back. Knee pads could be an asset.

3. Grasp the hammer firmly and hit the steel squarely. When collaring (starting) a hole, work deliberately and slowly, placing each blow carefully. Although a drill hole is usually started with a drilling steel, it can also be started by chipping slightly with a pick. In the beginning dust and rock chips are difficult to minimize. Be patient when collaring; a hammering rhythm is much easier to maintain after the hole has been started.

Establish your rhythm as soon as possible. Drilling with a regular rhythm will be more productive than driving the steel with powerful strokes in sporadic bursts of effort. Hard hitting causes you to tire quickly and experience cramping prematurely. It also causes the steel to stick in the hole. Take frequent rests to prevent cramps, and do not ignore signs of fatigue. Let the tools and gravity do the work.

Any rest that can be afforded your 'hammer-holding' hand while single jacking will help conserve your energy. A wrist thong may be attached to the end of the handle to help drill at unusual or difficult angles. The thong is looped around your wrist and lets you rest your grip a moment after each stroke. On the backstoke the fingers may be opened and the grip relaxed, allowing the handle to swing free but restrained from dropping by the thong. At the end of the backstroke the fingers close around the handle to prepare for the next swing.

Old time miner using a single jack equipped with
wrist thong, early 1800's.

Drilling continued...