Geotechnical core bits, although similar to surface-set diamond bits differ in that the cutting media are synthetic polycrystalline diamond elements. Divided into two categories, ‘TSP’ type and ‘PAX’ type, geotechnical bits are recommended for use when drilling relatively soft, abrasive, unconsolidated sedimentary formations that are not effectively drilled by surface-set diamond bits. The difference between the various types of geotechnical bits is in the degree of cutter exposure and the density (or number) of cutters mounted on the face of the bit.

 

 

 

 

 

 

 

‘TSP Type’ – Thermally Stable Polycrystalline TRIANGULAR-TSP

CUBIC-TSP

‘Pax Type’ or ‘PCD’ Type (Polycrystalline Diamond) R-Pax

 

T-Pax

H-Pax

TRIANGULAR-TSP

Recommended for use in consolidated to slightly fractured formations with a Mohs hardness range of 4 to 5.

CUBIC-TSP

Recommended for use in unconsolidated formations with a Mohs hardness range of 3 to 4.

PAX-SET

Supplied with large cylindrical PCD elements mounted in a matrix body bit crown, are recommended for use in softer unconsolidated formations with a Mohs hardness range of 2 to 3.

TSP-SAWTOOTH

Core bits with an aggressive saw-tooth pattern moulded into the face of the bit crown matrix body are to be used in very soft unconsolidated formations with a Mohs hardness range of 1 to 2. Typical formation types include gypsum and talc.