Bit Design
PDC bits feature a steel or matrix head, which is advantageous because
there are no bearings to wear out or broken cones to have to fish out of the
hole. The bit has a long, extended gauge with cemented tugsten carbide
wear pads to help maintain gauge. There is also inherent stabilization in the
bits extended gauge.
The face of the bit is concave, permitting several gauge and nose cutters to
attack the rock simultaneously, increasing stabilization while decreasing
the potential for deviation.
Jet nozzles vary in size and number, are interchangeable, and are
strategically located for maximum cleaning action of the cutters and the
bottom of the hole.
The cutters are arranged in one of three patterns:
• an open face, helical pattern on the face of the bit
• a ribbed pattern, with the cutters on ribs less that one-inch above
the bit face
• a bladed patters, with the cutters on blades, more than one-inch
from the bit face
All three types provide complete cutter coverage for a consistent
bottomhole pattern. One bottomhole pattern, known as kerfing, uses a
combination of scribe and round cutters to enhance the scraping and
shearing action of the bit.
Without moving parts, the bit shears the rock rather than gouging or
crushing as do the roller cone bits.
PDC bits feature a steel or matrix head, which is advantageous because
there are no bearings to wear out or broken cones to have to fish out of the
hole. The bit has a long, extended gauge with cemented tugsten carbide
wear pads to help maintain gauge. There is also inherent stabilization in the
bits extended gauge.
The face of the bit is concave, permitting several gauge and nose cutters to
attack the rock simultaneously, increasing stabilization while decreasing
the potential for deviation.
Jet nozzles vary in size and number, are interchangeable, and are
strategically located for maximum cleaning action of the cutters and the
bottom of the hole.
The cutters are arranged in one of three patterns:
• an open face, helical pattern on the face of the bit
• a ribbed pattern, with the cutters on ribs less that one-inch above
the bit face
• a bladed patters, with the cutters on blades, more than one-inch
from the bit face
All three types provide complete cutter coverage for a consistent
bottomhole pattern. One bottomhole pattern, known as kerfing, uses a
combination of scribe and round cutters to enhance the scraping and
shearing action of the bit.
Without moving parts, the bit shears the rock rather than gouging or
crushing as do the roller cone bits.
