I'm a month and a half into a lathe CNC retrofit, working part time. I was going to buy a Grizzly G0602 10X22 lathe and retrofit it, but a machine shop friend talked me into an old American made lathe. Those guys all look down their noses at the import machine tools, even though I think the parts I'd keep for the CNC retrofit would have been good (spindle, taper bearings, induction hardened ways). So I haunted Craig's List and found an ugly but lightly used Clausing 4902 lathe about 100 miles north of me for $1200. Buying it and getting it into my basement were epic adventures, but I won't bore you with that. The lathe is in the basement and I've been degunking it. The original owner painted it blue and it's now rough looking with age, but it's still tight and should be a good CNC retrofit.

Getting the lathe:




The lathe is finally in the basement:




I've been researching EMC2 quite a bit, and studying other people's CNC conversions. I'm an electrical engineer and I've designed many custom machines, so I'm not too put off by the electronics and wiring. As I researched EMC2 CNC and found good choices for subsystem solutions, I purchased the hardware. I'm well along the way. I installed EMC2 on a $100 used Compaq D51S Evo PC I bought off Craig's List for $100. It's running the EMC2 lathe simulator. I added a small Logitech K400 wireless keyboard with touch pad ($38 on eBay) that I think will be very handy and might take the place of a pendant. I have some nice Italian 900 ounce inch servo motors left over from my 2005 CNC mill project (never got a round tuit, but the mill CNC retrofit is next, after the lathe). I found some great $23 CUI encoders at Digi-Key. I have a couple of Gecko 320X servo drives. I took a chance on a 2HP Chinese VFD on eBay for $106 (looks OK, packing material smelled like Harbor Freight, Chinglish manual could be better but looks reasonably easy to set up and use). I have E-stop switches and shaft couplings and inductive prox limit/home switches, etc. I just spent $115 at Lowes on the wire, plug and outlet to wire the CNC lathe into the 30A dryer circuit in the basement. I bought a very heavy duty roll around tool cart at Sam's Club for $200. The PC sits on top, various measurement tools and lathe tooling go in the top five drawers, and the CNC electronics will go in the large drawer on the bottom with a lot of forced air cooling. Connectors to the lathe will be on the back of the roll around.

The roll around PC stand, tool cart, and electronics enclosure:




I still need to make some servo motor mounts and buy some fuses/breakers, connectors, etc. The only remaining big piece of the puzzle is the hardware to connect everything to EMC2 and the PC. I have a parallel port, but I don't think it'll have enough I/O. Should I add a second parallel port and use simple optoisolated breakout boards? Is there a better single board I/O solution that works well with EMC2?

I want the PC to be optically isolated from the rest of the electronics. I need to control the X and Z servos via the Gecko 320X drives and the three phase spindle via the VFD (0-5VDC, 0-10VDC, 0-20mA, 4-20mA, or RS-485). I think I'd like to use 0-10 VDC, and I may need a couple of outputs to signal RUN FORWARD and RUN REVERSE? I have four limit switches I need to read, as well as three quadrature encoders with index pulses (X, Z, and spindle). I plan on running the encoders single ended and not use the negative signals for A and B, so I'll need three inputs for each of the three encoders (A+. B+ and Index). I'd like some extra digital I/O because... call me crazy, but I eventually want to build a 5' bar feeder and collet/chuck closer so I can run semi-unattended operation for my short run production (up to 500 parts a month).

Got a good recommendation for an EMC2 friendly I/O solution, that's hopefully reasonably priced? Something that'll work well with my 24VDC digital I/O, the single ended absolute encoders, the Gecko servo drives, and the VFD to control the spindle?

I'm documenting this entire project, and when it's working, I plan on making a web page with a bill of materials, tips & tricks, and a series of YouTube videos to "pay it forward", and make an EMC2 conversion easier on those who follow me along this path.

Thanks in advance for any EMC2 I/O hardware recommendations you might have.