FILENAMES: chairscrew.jpg DESCRIPTION: This is a picture of a replacement stud for a swivel chair wheel. Posted by David Forsyth . David provided the following description: ================================================================== The image chairscrew.jpg shows the replacement stud I made for my office chair, and the old one. I felt it become wobbly and found the wheel had jammed and turned the stud out, then bent it sideways causing it to crack halfway through the threaded portion. Steel used is stuff from a printing machine roller and works nicely, could be leaded since the roller was probably made on a CNC lathe. Machine: Myford ML7 Cutters: HSS The shaft diameter is 5/16, the thread is Standard Whitworth 5/16-18 which I identified via Marvin Klotz' data sheets. (thanks Marv) I ground the threading tool by eye to be slightly sharper than a groove I filed in a piece of aluminium with a 3 corner file (which should be 60 degrees). worked fine. Note that I turned this at home without the benefit of having anything to screw it into. First test fit was this morning when I got to work. No problem with fit, only a bit stiff from the dirt in the hole which a drop of oil solved instantly.