The differential gears are nothing to do with prime but to add the traverse into the equation and also to add a rotation for a helical. I have a diagram of one at http://www.collection.archivist.info/hobbing.html
then you can wind the hob back along its cut traverse and it remains "in gear" Dave Caroline ------------------------------------------------------------------------------ Check out the vibrant tech community on one of the world's most engaging tech sites, SlashDot.org! http://sdm.link/slashdot _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
