Any device that may be attached to, or is, an integral part of a drill
string and is used as a cutting tool to bore into or penetrate rock or
other materials by utilizing power applied to the bit percussively or by
rotation. See also:detachable bit; drag bit. Long
A steel bit in which diamonds or other cutting media may be inset by hand
peening or attached by a mechanical process such as casting, sintering, or
brazing. Syn:bit shank; blank; blank bit; body; shank. Long
a. Technically, the difference between the outside diameter of a set bit
and the outside set diameter of the reaming shell. Loosely, the term is
used to denote the clearing action of a bit, which is a function of the
waterways and the mode in which the diamonds or other cutting media are
set in the cutting face of the bit, and also the difference between the
outside set diameter of a bit and the outside diameter of the bit shank.
Long
b. Incorrectly and loosely used as a syn. for diamond exposure.
See also:diamond exposure
The configuration of the crown or cutting face of a bit as seen in cross
section. Long
The central, removable, and replaceable portion or pilot of a noncoring or
other type of bit. CF:core
See:diamond count
See:crown
See:diamond matrix
See:bit mold
A bit with two or more rolling discs that do the cutting. Used in rotary
drilling through certain formations. Porter
A bit with serrated teeth used in rotary drilling. Hess
That part of the bit crown that comes in contact with the bottom of a
borehole. It does not include that part of the bit crown that contacts the
walls of the borehole. Long
See:feed rate
The average number of feet of borehole a bit may be expected to drill in a
specific type of rock under normal operating or specified conditions.
Long
The weight or pressure applied to a bit in drilling operations, expressed
as the number of pounds or tons of weight applied. Syn:bit pressure;
bit weight; drilling pressure; drilling weight; drill pressure; load.
Long
See:diamond matrix
A steel, carbon, or ceramic die in which the shape of a bit crown is
incised and provided with pips, grooves, or holes in which diamonds are
set and held by suction or an adhesive. Filling the die with a matrix
alloy by a casting or a powder metal-sintering process affixes the shank
to a diamond-inset bit crown having a shape conforming to that incised in
the die. Syn:bit die; crown die; crown mold. Long
The achievement of a bit as gaged by the overall cost of using a specific
bit per a unit measure of borehole drilled, or by the total number of feet
of borehole drilled per bit. Long
See:bit load
Obsolete name for reaming shell. Long
a. See:setting ring
b. Obsolete name for core bit. Long