A rotary drilling bit studded with bort-type diamonds. Also called boart
bit; boart-set bit. Syn:bort bit; bort-set bit. AGI; Long
Precision boring with a shaped diamond (but not with other tool
materials). ASM, 1
A thin, tabular chip of an uncut diamond crystal, weighing less than 0.75
carat. AGI
A cutting chisel having a diamond or V-shaped point. Fay
The plane along which a diamond crystal can be split easily. The four
planes paralleling the faces of an octahedron are those generally referred
to as the cleavage planes, or diamond cleavage. All crystalline diamonds
are more or less brittle and will be fractured by a sufficiently violent
blow, but the irregular surface of a fracture cannot be mistaken for the
brilliant flat surface produced by cleaving. The carbon has no cleavage,
and in ballas cleavage is absent or very poorly defined. Long
The act or process of splitting diamonds into smaller pieces, which may be
more readily used as tool points, gems, or drill diamonds. Long
The ratio of the area of a single-layer bit face covered by the inset
diamonds or, in an impregnated bit, the bulk proportion of the crown
occupied by diamonds. Long
The number of carats of diamonds inset in the crown of a diamond bit. Also
called stone content; stone weight. Long
A rotary-type drill machine using equipment and tools designed to recover
rock samples in the form of cylindrical cores from rocks penetrated by
boreholes. See also:core drill; diamond drill. Long
The act or process of obtaining a core sample of rock material using a
diamond-inset annular bit as the cutting tool. This tubular bit and
attached core barrel are rotated at a speed under controlled pressure by
means of hollow steel, flush-jointed rods through which water is pumped to
cool the bit and remove rock cuttings. With the advance of the bit, a
cylindrical core of rock passes up into the core barrel, where it is held
by a core lifter or other device. Long; Cumming, 1
a. The number of diamonds set in the crown of a specific diamond bit. Also
called bit count; stone count. Long
b. Sometimes incorrectly used to indicate the average size of the diamonds
inset in a specific bit. See also:carat count
The cutting bit in diamond drilling. It consists of a steel shell
containing small cavities in its face and edges into which black diamonds
are set. In some types of crown the diamonds can be removed and reset for
further use. Grooves, called waterways, are usually provided in the face
of the crown to allow the passage of the drilling fluid. For surface-set
bits in diamond drilling, it is recommended that 2 to 20 stones per carat
should be used in soft ground (such as shale); 10 to 80 stones per carat
in medium ground (such as sandstone); and 20 to 150 stones per carat in
hard ground (such as granite). See also:burned bit
With respect to atomic arrangements, similar to the diamond in having the
two face-centered cubic arrangements of atom centers either of which is
displaced with respect to the other by one-fourth of the diagonal of the
unit cube. Henderson
a. An individual skilled in the art of shaping diamonds as gems.
Long
b. A tool in which a single diamond, shaped as a cutting point, is inset.
Long
One of the three processes by which diamonds are prepared for use as
ornaments or in the arts, the others being diamond cleaving and diamond
polishing. Fay
a. A drilling machine with a rotating, hollow, diamond-studded bit that
cuts a circular channel around a core, which can be recovered to provide a
more or less continuous and complete columnar sample of the rock
penetrated. AGI; Long
b. Diamond drilling, a common method of prospecting for mineral deposits.
Also called adamantine drill; diamond core drill; rotary drill.
See also:core drill; hydraulic circulating system. AGI; Long
One who assists in the erection and operation of a core drill that bores
into rock, earth, and other minerals to obtain core samples. Also called
core-driller helper; core-drill-operator helper;
diamond-point-drill-operator helper; drill-runner helper;
shot-core-drill-operator helper; test-borer helper; test-hole-driller
helper; wash-driller helper. DOT
The act or process of drilling boreholes using bits inset with diamonds as
the rock-cutting tool. The bits are rotated by various types and sizes of
mechanisms motivated by steam, internal-combustion, hydraulic,
compressed-air, or electric engines or motors. A common method of
prospecting for mineral deposits. See also:diamond drill
The core brought to the surface in the core barrel. The cuttings in the
uprising drilling fluid will also provide sampling material.
Syn:core recovery
a. Finely fragmented or powdered diamonds used as a cutting, grinding, and
polishing abrasive or medium.
b. A diamond powder produced in the cutting of gems.
The proportional mass of a diamond protruding beyond the surface of a
matrix metal in which the diamond is inset. CF:bit clearance
Syn:stone exposure