Looking into converting my Mill to CNC

[irving2008]

The main issue with round-column mills isn't so much the strength, unless you're trying to hog out large cuts in steel, its the lack of registration on the head. To CNC the Z-axis you can only really drive the quill which limits z movement to 100mm or less. Changing tooling often means raising the head and then you lose positioning in X-Y. While there have been many approaches proposed to address this in the end none are truly satisfactory. a square column mill wins hands down in this respect.

Can I suggest you don't Pump a lot of money into this converting this machine as they are not very suited to CNC conversion being round column and relatively low strength.

Buying quality parts for the Electronics is recommended ie: Drive's, BOB, PSU etc as you can take these with you to another machine but I wouldn't go to great expense or trouble on the machine it's self. Ie: Zero backlash Ballscrews etc and would just do the minimum required at first with lead screws on it already.
This will give you an idea of what's involved and also show you the limitations of the machine under CNC control.

If you do go to the trouble at first it will seem great has your not used to CNC but it won't take long before you start to see it's failings and want better from the machine and start chasing it.
In time it becomes like digging a ditch your so far into it's hard to to get out and you pump more and more energy and money into it but the reality is you can't make a silk purse out of a sow's hear and your still stuck in the ditch.!!

[magicniner]

Not all round Column mills are created equal ;-)
My Emco FB-2 based manual mill (the conversion I have planned) and current CNC - a Rishton based Connect are both round column but have good Z travel with excellent registration and gib strip adjustment.
I've considered doing the work to machine a slot in the column and add registration with gib strip adjustment to my floor standing mill-drill, then I remember how heavy it was when I assembled it :-O

- Nick