All, Just to revise my last post, all but three of the knobs are 6mm-dia spline fitting. The odd ones are 6mm-dia grub screw. Cheers, Neil -- Neil Johnson :: Computer Laboratory :: University of Cambridge :: http://www.njohnson.co.uk http://www.cl.cam.ac.uk/~nej22 ---- IEE Cambridge Branch: http://www.iee-cambridge.org.uk ----