On Thu, Jul 4, 2013 at 9:05 AM, Gregg Eshelman <g_ala...@yahoo.com> wrote: > I did some rework of some poorly welded up teeth on a back gear for a South > Bend lathe made in 1914. Built up with brazing then took advantage of the > gear having an odd number of teeth. Set in the bottom of my mill vise on two > teeth so one tooth pointed straight up to cut the tip down, then used a pair > of pieces of metal the same thickness to position the gear with one tooth > straight down so I could cut through the middle of the gap with a small ball > end mill. > > Then I rotated the gear to various positions to cut three different angles on > the sides of each tooth, gauging by eye for when I had enough of the brass > cut down. > > When done it was almost good enough to use. After a bit of work with a file > to smooth the edges it rolls around the gear on the spindle quite well. > Workable for a few teeth on an existing gear, not so much for cutting a whole > gear from scratch. > > Now imagine the gear mounted to a 4th axis and all the turning and > positioning handled by the CNC, and making 4 or 5 angles per tooth side. > Would only need a single ball end mill to cut a huge range of gears. It just > has to be narrower than the bottom of the gaps between the teeth. I had to > use a quite small end mill to do that gear. 16 DP would need a smaller one. > > A slitting saw or small horizontal mill cutter with a rounded edge would > likely be faster on smaller teeth like 16 DP. > > Still don't have a CNC mill of my own. :-P
I built my mill to cut gears, usually clock gears with a form cutter but added a 5th axis to allow other methods The radius on a ball endmill works against your needs you would have to under cut to to get the right form near the root the best result form is to use some form of generation, but for repair work grinding up a form cutter with a microscope and a dremel is not too hard. that is how http://www.youtube.com/watch?v=HAtziCsUj5Q is done Dave Caroline > > ------------------------------------------------------------------------------ > This SF.net email is sponsored by Windows: > > Build for Windows Store. > > http://p.sf.net/sfu/windows-dev2dev > _______________________________________________ > Emc-users mailing list > Emc-users@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/emc-users ------------------------------------------------------------------------------ This SF.net email is sponsored by Windows: Build for Windows Store. http://p.sf.net/sfu/windows-dev2dev _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
