4th axis drives

I am almost done with the retrofit on my mill and am now looking at the 4th axis options. The rotary tables that Ajax sells are just too expensive right now so that leaves me with a couple of options: Buy a used rotary table and retrofit it, or build my own. I can either buy Ajax's 4th axis drive, which is still a bit pricey, or I can try to use a different drive. Most of the low cost 4th axis systems are stepper driven which is fine for my 4th axis projects because they will typically be small and low volume.

So my questions:

What drives are compatible with the Ajax controller (what have you successfully used)?

Can I run a stepper driver with the Ajax Control?

Anyone build a 4th axis using a rotary table? Any advice?

I've got the 4th axis Centroid drive/software unlocks which I'll hopefully be hooking up soon to a NOS Yuasa 4th axis rotab with a Fanuc DC brushed servo motor. That's with the standard CPU10 control board/DC3IO 3 axis servo drive/PLC setup.

My impression is that if you've got the regular CNC10 motion board/DC3IO servo drive & PLC combo then you've pretty much got to run the single drive from them as the motion card is designed to interface via the fiber optic cables with the Centroid drives.

They appear to have another motion card and PLC board (MPU11/GPIO4D) that is more universal and will work with 3rd party drives but that seems to be an entirely different platform and that you need to go one way or the other right from the start.

You are probably going to need to contact Ajax/Centroid and get some firm information on just what will or won't work.

cheers,
Michael

The only choice you have with your setup is to buy the drive for $865. I have done 2 4 axis ajax retrofits on bridgeport series 2's and both turned out great. Its well worth the money and the controls are reliable. The new linux software is great. It never locks up on me......not once in 2 years!!!!!!!

For me the drives aren't the prohibitive item, it is the actual rotary table. The ones Ajax sells would basically blow my entire tooling budget. I have been watching ebay, but it seems like those tend to be very big (>10") and heavy for my table which has a 500 lb capacity. On top of that they are still pretty pricey. What have you guys done for the rotary table?

I got lucky. :)

My 8" Yuasa was bought as a spare in a commercial shop and the mill it would have gone on was worn out and scrapped before the rotab ever had a servo motor put on it. The person who bought it from the original owner (a friend of his) was going to use it on a small VMC but found it was just a bit large for fitting inside the enclosure so he never used it. So he had it sitting on the shelf, never used by anyone, when he sold it to me.

The price was definitely right but that's not the kind of deal that comes up frequently. Watching eBay is probably going to be your best bet unless you can go to an auction and find one that no one else is interested in.

cheers,
Michael

I run a SMC RTC210 rotary table. I think there is one on ebay now. anyways......the DC servo motor that is in that rotary table will work with the ajax drive....just got to wire it up right. the schematic is under the cap of the motor. Its a really nice table, i picked mine up for 1500 with a tailstock.

Let me know if you need more info.