Team 975 once had to hone out a pair of 5/8" bore flanged steel sprockets to fit a 16 mm shaft. I figure it was probably .004" or so. We used a 5/8" shaft in a drill press and a lot of valve grinding compound. It took a lot of time but the fit was beautiful. Next time that was needed, we just spun the shafts and sanded them down to fit. Much easier.
