Thanks for the kind thoughts! A project that has intrigued me is something called the Balshazar Backing Off device. Invented back in the 1890's it form relives things like involute gear cutters. Rather than my trying to describe it's operation just google it! There is a video of a version that has a hob and drag leadscrew backing off a gear hob! Amazing to watch! Producing a form relieved involute hob is pretty high end machining! Bill in Boulder CO USA