Gene...
In theory what you wish to do is possible, but in reality, very difficult for the inexperienced. Here are the reasons:
1) Without gear reduction you would have a 0.318.. turns ratio. Far below what is required for Centroid. That direct drive alpha was so bad that SB traded them out for gearmotors after realizing their mistake. You would have to add gear reduction. Currently SureGear N34 5:1 gearboxes are $471 each.
2) If you do add gearboxes, the OEM swing brackets are not strong enough to handle the torque nor the overhang weight of the gearbox & motor.
2) ShopBot used some wonky drive programming on those drives to try and get them running well. Plus, they used a "resolution multiplier", which was actually a resolution divider as is reduced resolution by a multiple of 4 during rapid moves. You would need to have the drives reprogrammed to be able to use them. ShopBot won't do it and they have the "magic encoder ring". You may be able to source drives with OEM programming on the web.
3) It would be a nightmare to try and run the IO and step/direction from the Acorn's DB25 thru that old IO board as many of ShopBots signals are inverted, i.e., ttl high (source), where acorns signals are ttl low (sink). You would have to design and build a "gender changer" for the signals. Plus those old components may not be up to handling data at modern speeds. That vintage signals were in the ~30khtz range and out current builds are using 200Khtz.
4) That hardware is at least 20 years old and is using 30 year old technology, getting it to marry up and work well with a modern controller would be difficult for the experienced. A never ending nightmare for the inexperienced.
5) Now you know the reasons that I started building replacement controllers in 2014. And why I have never looked back.
EDIT: P.S.: I have a spreadsheet with the crossover pinout from when I tried this years ago. Its yours if you want it.
