Hi everyone and welcome back to my nightmare. Actually this time it's a dream come true. Last week I had discovered the Tormach Rapid turn and thought that's a great idea and not as pricey as the other guy running the Servo setup with brake, etc. So I decided to check Ebay and low and behold there was a used Rapid turn with all the goodies for a good price. Bought it on the spot. Now how do I hook this up to my CNC running Mach 3 when all the warnings from Tormach say that it can only run on there magic software and it's made only for the 770 and 1100. Well I called B.S. on that. So here we go.
I started by running a dual VFD setup that I can control manually. This way you have the best of both worlds. By running both the Main spindle and Rapid turn spindle now you can do precision grinding and other things I have not thought of yet. I also installed a switch so I flip flop between the Main spindle RPM and the Rapid turn RPM in Mach 3. The Index seems very solid, I can't wait to cut threads.
Next I installed a 900 in.oz. stepper on the other side directly across from their 3 phase motor using an almost exact copy of there motor mount bracket except for making it fit my stepper, that way all you have to do is swap the belt to the stepper pulley. Easy Peasy. It's a safety thing too, you don't ever want to drive the opposite motor when your working. I used their motor belt pulley on the stepper but had to make a thin tube as the nema 32 stepper has a .500 shaft and the Rapid turn motor shaft was about a .556. No big deal, bore a piece of aluminum tube then cut down to size sneaking up on it, I wanted it perfect.
So that worked great. I did have to replace their junk set screw as it strips right out because it's so soft. I counter drilled the set screw hole and used a 10-32 allen bolt and it worked perfect. It went through the larger pulley as I would not use that pulley for the 4th axis anyway. It's about a 3.5 to 1 ratio so the braking action of the stepper should be fine. I tried it and I could not turn the 4" chuck by hand, it was solid. I could not even get the belt to slip.
So of coarse using a multi grooved belt is suppose to be a huge no no when indexing and I would agree if I was making huge cuts and pushing every limit. For what I'm doing and about 90% of the home machinists I don't think it's a big issue. Scrolling, cutting splines, rotary engraving, making flats etc. I don't see any issue doing these.
The biggest issue I ran into really was just getting the Proximity sensor to work. So I put in a picture of that too. Pulled my hair out until I tried the 1.5K resister across the power and signal. Works like a charm. The drawing is the stock Tormach cable with the end cut off.
OK, The picture with the cutter and splined shaft was a setup picture. Just trying to show what could be possible. I did this splining actually on another 4th axis of mine on this machine with no brake just index with the nema 32
stepper. Actually same stepper, I robbed it for this.
Next step is figuring out a gang tooling setup, that should be fun.
Anyway I hope this helped some people out with running a Rapid turn on a non Tormach. I may put it on my Skyfire VMC2 when it arrives.
The nice thing about the Charter Oaks mill is the bed is long enough to just leave the Rapid Turn on there, still plenty of room for other projects.