Bit classification code

Bit classification code

H:Very hard to hard rock> 2500 bar (250 MPa)

M:Medium hard rock..1500-2500 bar (150-250 MPa)

S:Soft rock< 1500 bar (150 MPa)

C:Homogeneous (competent) rock

F:Fissured rock

V:Very abrasive rock> 40% silica

A:Abrasive rock..20-40% silica

N:Non-abrasive rock..0-20% silica