I just got the Mill Arbor for a Sherline Mill and need the know the spindle speeds for a 16DP 55mm HSS involute gear cutter set. The big machines run these cutters slowly, around 100 RPM but I don't think the little Sherline motor can generate enough torque at that slow of a speed. I have tried light cuts and higher speeds seem to cut better but I am afraid to damage the cutter with a long series of cuts until I have more information. I am cutting Delrin, 6061 Al and Brass.