DRILL BITS AND TOOLS FOR SUBTERRANEAN DRILLING

摘要

A drill bit (10) includes at least one extension pad (30) extending rotationally forward backward of an associated blade (24) in a gage region (23) of the bit body. The extension pad includes a circumferential bearing surface (32) that extends the circumferential bearing surface of the associated blade and reduces the chordal drop between any blade havi an extension pad associated therewith and a circumferentially adjacent blade toward which the extension pad protrudes. A drill bit that reduces a chordal drop segment extending across a junk slot is also disclosed.