Dividing headstock

[brian]

Could a dividing headstock be used for making a indexer.I,ve been looking at some on ebay and it seemed like a cheap alternative to buying and adapting a lathe

[eaglesplsh]

The short answer is yes...

There are a lot of folks who have done this. You can probably find something like this pre-built for sale on ebay, as well.

I looked into doing the same thing last summer. The dividing head presents some challenges, which is why I went another route:

First, most of them don't include a chuck. Mounting a chuck on some of them will require significant effort.

Second, most of them don't include a tailstock. By the time you add in the chuck and tailstock you're probably about even with the cost of a cheap lathe from Harbor Freight.

Third, a lathe bed should simplify the process of maintaining alignment between the chuck and tailstock. (This precision may not be important to you, or you may not mind spending time dialing things.)

Fourth, linking a dividing head to a stepper motor shaft and mounting the stepper motor to a funny shaped casting/housing may be a challenge. (I found it was easy to link the stepper to the lathe shaft - plenty of room inside the head for a timing belt/pulley. Also plenty of mounting surface to hold the stepper motor.)

Fifth, the gear ratio that the dividing heads use can be really slow compared to direct drive. These things are meant for hand cranking on a metal cutting mill. Stepper motors loose torque when run at high rpm, so you may be forced to run the 4th axis slow and have problems with chipload/heat, throughput, etc. (If you go with the cheap lathe/timing belt setup you can choose your own ratio for precision/speed.)

Sixth, I assumed that the cheap dividing heads would have problems with backlash. You may be able to reduce backlash in the begging by adjusting nuts, etc. but that puts pressure on parts that will eventually wear down. Timing belt/pulley drives have zero backlash.

Seventh, the mass of the cheap lathe castings should reduce vibration. They will also give you better mounting options for holding it to your machine.


...Don't mean to rain on your parade with all this. I just figured I would share the logic that I came up with when I made my decision, in case it's helpful to anyone else.

Either way you go, you may get your 4th axis built before I do. I did all the research and most of the design work + bought the lathe, chucks, pulleys, etc. back in August. The rest is maybe a one day project. I'm hoping to finally have time to finish it when orders slow down after the holidays...

Anyone have a date when the new 4th axis software is coming to PartWorks? The Aspire improvements look great.