One of the good things about TurboCNC is that it runs under DOS. With no multitasking, DOS has full command of the processor and generating steps. Step generators are for Windows based software, solely to eliminate the evil multitasking errors. When I did mine, TurboCNC was a free download that you could try and ~$60 to buy. I haven't checked in years, but I suspect it is still along these lines. And, with DOS, any old POS processor (even 386's!) will generate more than enough pulse speed, way more than enough. I use the free FlashCut demo to view tool path (see screen shot I posted earlier). There are some codes for TCNC that FlashCut doesn't recognize, so I get the toolpath straight and then add the code for pauses etc. before I run it. (After adding this stuff FlashCut balks on the extraneous code, no biggie really. Just an order to do things) For me it goes: Draw the part in AutoCAD-export .dxf, Convert to g-code using FlashCut demo and play with tool path, Add code for torch on-off and preheat etc. in NotePad, Change the file extension to .cnc, Run it in TCNC. Not as hard as it sounds and all free or cheap. I have two machines. One is screw driven (direct mounted steppers) and rapids around 100ipm. This is the 30" machine and I don't really need the speed for the torch (usually around 30ipm). It works very well. The other is 4'x6', rack driven (4:1 reduction) and rapids as fast as 1200ipm. I built it for a friend to use as a plasma machine and bought it for chump change when he lost interest. I have slowed it down to 6-700ipm because 1200ipm can be scary (and un-necessary). The little Y gantry is ~70#, the big must be more than 100#. Both are single motor on the X. The little has 187 oz motors, the big is powered by ~900 oz motors. I don't think you really need a dual drive X unless racking on the guides is a problem. I did the big motors on the big one because I might put them on my bench mill someday and the machine is a router right now (I knew I might get it someday ). As a torch, 900oz is WAY overkill. There is no tool load to overcome. They did give me unreal accelleration and rapids though (fun to show your friends,100+# going 0-1200ipm in .2sec and an inch or so is COOL. Too much fun and you'll break a gear or strip it off the shaft though). The little is driven by Xylotex, the big by Gecko's. And, since my Plain Jane hand torch will cut 5" steel (I believe it, it goes through 1" like butter), a 3-hose system may not be necessary either. I just use a solenoid triggered air cyl. to push the torch's button. No other valves. I have used a trim router and Z slide on the little one too. It works, so you really don't need a ton of power to push 70# around, even with some tool load. Don't be drawn in to over-engineering the thing, it is amazing how far simplicity will take you. You will have plenty of effort involved in making the machine, even a simple one, if you plan on doing it well. Mine has had ZERO adjustments to the design since I started using it. I have knocked out a ton (maybe literally) of cool stuff with it. I guess it has been at least a couple of years. I wish I had made it at least 4' wide in one direction, I have to cut sheets to get them in it. My dimensions were based on a 6' acme screw, cut in half. I'd have spent the few more beans for more rod had I thought about it.
I somehow got un-subscribed from this thread so I missed some of the exchange. I'm re-subscribing this time so I can watch your progress, POST PICTURES. Good luck, MIKE