CNC back to manual control???

[mobjack68]

Newbie here...need some REAL help. I have 2 (two) Boxford Duets...for those that are unfamiliar with the machine, they are more like toys than anything else, combination lathe/milling machine. 4" chuck, 8" swing, 24" ways, BUT they are (were) CNC. Here's the problem. These machines were used for training at our local trade school. When they upgraded to "big boy toys" these 2 were passed down to the middle school and were used by grades 6, 7 and 8. (I'm in the US, British would be year 12, 13, 14) 1 has a blown circuit board, I experienced this failure when I connected them to the computer and I am afraid to plug the other one in for fear of the same problem. Boxford no longer supports this product, replacement circuit board has been elusive at best. I would like to convert the machine with bad ic board to manual control. It is a great combo lathe/milling machine and I would like to try my hand at it. Is there such a creature as a commercial stepper motor controller that does not have an outrageous price tag??? I have considered an upgrade for the electronics (the computer program I have to support these guys is DOS 5, which means writing binary to construct a program .....??? I think??...) Anyway, it seems logical that a manual controller could be applied to the stepper motors to give control.....thoughts???...suggestions????

[malb]

mobjack68,
Should not be hard to find modules that will drive the steppers for you, but what do you want to use to control the modules. From your post, I envisage you manually operating a couple of wheels that encode your movements and past them to the stepper controllers as input. If that is the case, why would you want to?

That sort of scenario would give you the worst of both worlds, a manual control machine with no feedback or feel as how the job is going.

CNC doesn't need a lot of 'feel' but normally has limit switches, current sensing etc build in to ensure that the movements stay within safe bounds. It's beauty is that once a program for a part is developed and debugged, it can be used for ever to make the part. As such it does not need a lot of feedback, the only real variables in the equation is tool wear and resetting.

With a wheel command stepper system, you would loose all physical feedback, without having the ability to have the machine repeat a programmed and known viable pattern of movements to machine the required part. A lot of the skill of a conventional machinist is in interpreting the physical feedback or 'feel' to optimise feeds and cuts etc for efficiently producing the part.

It might be better to consider a retrofit with modern electronics similar to those used in homemade or kit equipment so that the machine has CNC capabilities and a modern computer/machine interface for development of parts.

I'm sure some of the guys here could chip in with some info in that direction.