Perfect headset performance requires accurate machining of the fork crown race and this is the tool to do it cuts the outer edge and lower surface of the crown race seat a simple adjusting system allows the tool to be a tight fit on all forks threaded or unthreaded including those with externally butted steerer tubes includes high speed steel cutters and adjustable collets sufficient to cut 265 mm or 271 mm crown race seats on 1 inch forks and 301 mm crown race seat on 1 18inch fork