There are many causes inducing rock bit cone break, in which the effect of its machining on the cone is more serious.

Dynamic model of roller bit with nine degrees of freedom;

Computer simulation for the side-cutting of roller bits;

Model to determine rock drillability by roller bit;

The calculation of contact stress of rock bit floating ring journal bearing under disalignment;

Application of computer simulating technology in rock bit floating-ring journal bearings;

The coupling function analysis of the thread-locking ring of rock bit on axial load;

Simulation of rock disintegrating process by roller cone bits;

Applicant research of bored piles into the hard rock with roller cone bit;

Design and processing control of slide bearing clearance of roller cone bit.;

Breaking cuttings mechanism of cone bits and fractal method for rock drillability;

Application of deep end-cavity cylindrical roller bearings to cone bits;

Elastohydrodynamic lubrication of tapered roller bearing on new high-speed cone bits;

A singular one-cone bit is designed.

In order to find out the best kind, we can give some good advice to the water system design of one-cone bit.

Because one-cone bit has the advantages of the three-cone bit and the PDC bit and it makes for their disadvantages, so the one-cone bit is the important chose to drill the small well.