Abstract: The bench test of three-cone bits and analysis of their bottom hole patterns are the simplest and useful means of checking and improving their design. These means have been rsed for a long time abroad, but they are used in our country for the first time now.
In present paper we have introduced in great detail the measured parameters and the bottom hole patterns of the Sichuan-made three-cone bits, such as “XHP4-1、川,M-9X types, when we used them to penetrate granite, limestone and sandstone. In addition, we have compared all these results with those we obtained, using bits of ”J44、J55R、F3、HP51、J77、types, which are made in U.S.A.
Besides, in this paper we have presented several photos of bottom hole patterns and various drilling parameters. Through theoretical analysis of them we have come to some conclusions about the rational teeth arrangement and usage, which may be useful for improving bit design and its usage.