Cylindrical cutting head forms extension of borehole drill pipe

摘要

The cutting head for use in sinking cased boreholes has a body in the form of a cylindrical ring that makes an extension to the drill pipe. The cutting head has teeth uniformly spaced around its periphery. The teeth (4) are indirectly joined to the body by sleeves welded into, and completely filling, recesses in the body. The sleeves have recesses for the fitting and securing of feet (5) formed on the teeth. Several features and variants of the cutting-head design are claimed.