Thanks Alan -- very nice. I've long admired your Stepperhead lathe. It is a full CNC machine running on CNC software, not an electronic change gear project, so it seemed more appropriate to show a video of its screwcutting capability here.
If it's using TurboCNC, I'm guessing it uses a hall effect sensor for feedback while screwcutting, rather than an encoder, but I could be wrong.
Did you ever build Stepperhead 2?