Jeebus ryobi makes chit complicated //content.invisioncic.com/y282845/emoticons/biggrin.gif.d71a5d36fcbab170f2364c9f2e3946cb.gif Not the bits , they are 1/4" shank. I have the same kit . Something must be wrong with that collet adapter //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif