I have had 3 of these Dewalt hammer drills and they do the job. lots of power, chews hairpins with a large snail with no problems. On each of them (only 4 months on this particular model) the cartridge is stuck and cannot be repaired. He gets stuck. and after researching the only way to fix the problem is to replace the cartridge. The only way to change the chuck is to completely disassemble the drill, gear case, motor, etc. Sorry Dewalt, one star - I'm not kidding, this has happened to me 3 times and I'm done.