What is a good indexing head/super spacer to convert to 4th axis?

[cjjonesarmory]

I've been trying to figure out what brand and model of indexing head/super spacer (as they call it) would be suitable for converting to a 4th axis for my milling machine.

I want one that has a chuck instead of just a mounting plate. I know there are chucks that you can mount onto a plate as well, which would also be fine.

I attempted to convert my small 6" Grizzly Industrial (no name brand really), but it had way too much backlash in the gears. I started to disassemble it and see if I could replace the gearing, but I got tired of messing with it and would rather just get a more suitable one in the first place.

Only requirements I can think of are that it has to be sturdy, extremely low backlash, and preferably has a chuck instead of a plate. I just figure there are guys in this forum that have done this before and could give me advice on what they used. I already know how to machine mounts and etc for the motors, just don't want to blow my money on an expensive rotary table/index head/super spacer (etc) and find out it won't really work well.

Thanks!

[awerby]

I'd suggest the Sherline 4" rotary table (#3700 CNC): http://www.sherline.com/3700cncpg.htm . It has a t-slotted faceplate and a threaded adapter so the Sherline and Taig chucks both fit it, and it comes with a mount for a NEMA 23 frame motor. You can make your own mount for it to run it in the vertical position on your mill. It has a 72-1 gear ratio, and very low backlash. I've gotten a lot of use out of mine, and my customers are pleased with them as well.

Andrew Werby
www.computersculpture.com