Here is my latest project. It was a Dahlgren System 500 in its previous life. I have modified it by the following.
1: Removed the air operated Z-Axis and replaced with a Stepper driven Z utilizing the origional Engraving spindle. In this configuration it will use the T-slot table measuring 24" x 20" with about 1in of Z-axis travel.
2: I built another dovetail mount and added 4in travel delron slides. To this I mounted the stepper and a mount for the trim router. I then only have to slide in the router assembly, remove the T-slot table and replace with a drop table made of .25in aluminum and this gives me a total of 4in of Z-Axis travel. This also allows for a vacume system to remove dust and chips.
3. I am using the origional SCU unit (engraver control) enclosure and the powersupply. I gutted the other electronics and added three API CMD-260 microstepping drives as well as a PMDX-120 Opto-Isolated Breakout board. This drives the steppers at just under 65Vdc.
4: All the mechanical retrofit is done, I just have to connect the steppers and hook up the limit switches and it is ready to go.
5: All this is under a 1/2 in Plexiglass enclosure for dust and sound control.
I bought it at auction and stripped out the old dos control to make room for the new conrol modules. It actually worked fine for engraving but since it used an air driven Z axis, it only had about an inch of clearence. Hence, the spindle conversion.