At last, more progress on the tool making. After breaking the cutting tool while making the hob for the worm wheel, I started looking around for off-the-shelf worm drives. A low backlash one came up on eBay for $100 including a stepper motor, so I jumped.
After some deliberation, I decided that I would attempt to make my own worm gear and wheel for my electronic indexing device. While it’s possible to buy the gear and wheel from companies such as HPC, the low backlash type that I want commands a high price. Besides, it’s an interesting project in itself.