A while back as I browsed through Nick Carters extensive Taig Microlathe pages, I saw his little 60:1 dividing head. A beautiful little thing it was! He utilized the extremely accurate Taig Microlathe standard headstock as the heart of the unit which he indexed through a 3/4-10 worm driving a 60 toothed gear mounted to the pulley side of the spindle. The worm gear casing was mounted so it could be pivoted up and down so the proper mesh between the two could be easily maintained. The crank operating the work also featured a finely crafted dial with 60 divisions of its own. Turning the dial one full revolution, causes the main spindle to rotate 1/60 of a revolution or 6 degrees. Advancing the worm gear dial ten divisions translates to a one degree rotation of the spindle. You could thus create a 360 degree protractor completely from scratch, generating each of the divisions directly with the dividing head. An advance of a single division of the dial rotates the main spindle only 1/20 of a degree. Quite an amazing little tool! I simply had to make one for my shop.
After a little consultation with Nick, I began to plan my version of the dividing head. I originally planned to also use a Taig headstock but since I was already in the middle of a major project also utilizing a Taig headstock, I decided to fabricate it completely from scratch and save some much needed funds. I wanted to have no only a headstock block that could be clamped to the milling machine, but one that could also be clamped onto the Taig microlathe bed, replacing the standard headstock. This required the milling of dovetails. Although the scratch built headstock would sport similar dimensions, it would also function in the same manner, clamping onto the dovetailed bed via a large clamping slot plus two 1/4-20 bolts. If you take a look at the Taig headstock, you will have a clearer image of what I am talking about. I also decided I would keep the same basic gear ratio as Nicks. During my talk with Nick I realized that he had simply used a short length of 3/4-10 threaded bolt for the worm and cut the 60 tooth gear using a simple fly cutter affair swinging a standard 60 threading tool.