We bought a second hand Hermes Vanguard machine some time ago. It had its own controller too - however, we don't use it.
I am quite sure that the existing control circuitry would be very difficult to setup with Mach 3 - I have found no information available on the internet. There is a good chance that the parallel port is uniquely wired (not to the standard).
What we did was just take the wires from the stepper motors and limit switches (some rewiring (extending of wires) had to be done to the unit underneath), and connected them directly to our own driver board, which we made up with components from
http://www.kelinginc.net/, however, we will soon be converting to a smaller design using the GeckoDrive G540 (
http://www.geckodrive.com/product.aspx?i=14469) – this also does not require an isolated 5V power supply like the boards from Keling do. We are planning to use the SmoothStepper as well.
We discarded all the old controller circuitry. Connected to a Pentium 4 PC with Windows XP and a parallel port, the machine is running very well.
Another thing is that the machine had a 120VAC motor on there for the tool holder. We also removed this, and replaced it with a motor from an old battery drill (of course, we had to redesign the tool holder as well) – however, this is not that powerful, and is very noisy. We are going to try a brushless motor, and add a vacuum system to get rid of the dust. We are just planning to cut PCBs and shapes out of wood. I am not sure if the machine is powerful enough to handle aluminium – the steppers are only rated at 1.5A.
Sorry, I cannot remember the model number of our unit.