BORRCHUCK I TVA DELAR FOR DJUPBORRNING

摘要

Disclosed is a two piece drill chuck for use with downhole drills and the like. The new chuck features a replaceable wear collar portion which permits optimum material selection and heat treatment for each part of the chuck thereby extending its useful life. By expanding the wear collar slightly beyond the drill diameter and extending it axially rearward an improved measure of protection is also afforded to the drill casing.