I can't count how many Oregon 40466 file kits I've bought. The 6" smooth file is a good quality or seemingly so but boy don't the file teeth get polished in a hurry and quit cutting. I've actually gone looking for a medium diamond tool to see it it would last longer but I haven't found something that will fit the depth guide/gauge. I don't think its chrome on the depth gauge in front of the tooth because I purposely used a fresh file on a previously dressed depth gauge and the file still gets dulled quickly. My round files last a fairly long time but not the flat files. Anybody have ideas?