A drill used for making all but the first part of a hole, the first part being made with a drill of larger gage.


Related Terms

DRILL

Organized activity for teaching or practicing specific procedures.

POLE-DIPOLE ARRAY

An electrode array used in a lateral search conducted during a resistivity or induced polarization survey, or in drill hole logging, in which one current electrode is placed at infinity while another current electrode and two potential electrodes in proximity are moved across the structure to be investigated.

PNEUMATIC DRILL

Compressed-air drill worked by reciprocating piston, hammer action, or turbo drive.

PLUG CUTTER

A device for boring out short dowels or plugs from wood that exactly match standard drill sizes.

PLASTER SHOOTING

A surface blasting method used when no rock drill is necessary or one is not available; consists of placing a charge of gelignite, primed with safety fuse and detonator, in close contact with the rock or boulder and covering it completely with stiff damp clay.

PERCUSSION DRILLING

A drilling method in which hammer blows are transmitted by the drill rods to the drill bit.

PERCUSSION DRILL

A drilling machine usually using compressed air to drive a piston that delivers a series of impacts to the shank end of a drill rod or steel and attached bit.

PENETRATION SPEED

The speed at which a drill can cut through rock or other material. penetration test

PANCAKE AUGER

An auger having one spiral web, 12 to 15 inches (30 to 38 centimeters) in diameter, attached to the bottom end of a slender central shaft; used as removable deadman to which a drill rig or guy line is anchored.

OIL-HOLE DRILL

A twist drill containing holes through which oil can be fed to the cutting edges.

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