2 Attachment(s)
YADH - Yet Another Dividing Head
Attachment 9266 Attachment 9267
Pictured above, is a dividing head I built from a gear reduction drive that I found at the local metal recycle yard. There were a number of them laying in a pile, and I grabbed a pair that looked to be suitable for my purposes. As it turned out, the gear box had a 60 tooth worm gear and worm. The input and output shafts were fitted with tapered roller bearings by the manufacturer, which meant they could handle any loads I would be presenting it with. The gear drives were cheaply aquired, as the recycle yard sells items like these, at scrap mixed-metal prices (by weight). As soon as I arrived home, I set about refurbishing them. After a good cleaning, machining, installation of new bearings, etc, one of them was ready for service. I coupled the input shaft to a 400 step stepper motor, and an Arduino controller with motor driver and power supply (also described on this site).
Also mentioned in an earlier tool post of mine, I recently purchase a used 10" South Bend lathe. This allowed for production of a threaded adapter, giving me the ability to fit a 3 or 4 jaw lathe chuck (or backing plate) to the output shaft of the gear drive. The gear drive output shaft was originally designed to drive from either end. Not wanting the interference of a shaft end opposite of the one I planned to use, the undesired end was cut flush with the outside of the gear drive housing. I used the off-cut from the output shaft, to make a input shaft coupler for the stepper motor.
In total, the 60:1 worm drive coupled with the 400 step stepper motor, gives a resolution of 24,000 divisions. While I don't plan to cut 24,000 tooth gears, I think it does provide for a greater range of divisions.
Thanks for reading, and I hope you find this useful! :)
-EN