That would be a good choice to CNC, IMHO the bed or column style mills are better suited for CNC than knee mills. If you do take the plunge, there is plenty of talent here that can help with any questions you may have.
BTW, I have a similar mill I am planing a CNC conversion on, as soon as I get the rest of my shop together...
If you are looking for a manual mill to eventually convert, the 940 is a great machine. I believe it is even offered with hardened ways (at least it was when I bought mine), so it should last a long time. The 940 is also available in a CNC version, but it's not on the website. This is the model that I have, and am very happy with it.
I would also check out the 833T... Looks like a killer machine. I wish it would have been available when I purchased my 940 CNC, and I would have known enough to CNC it back then..
My friend has a true RF machine, made in Taiwan. There is no question, it is a few notches above the machines made in China proper. The fit and finish is very nice. I have inspected the pictures of the 833t very closely and it looks very comparable to his RF machine, including the scraped ways. The "Main High Quality Features" section of the 833t page is pretty much a list of reasons that I wish I had it.
When I got into this, it was because I switched jobs when I just started seriously learning CNC. I decided that it was a skill that I wanted to have, so I considered getting a manual machine and converting it, but in the end decided I was less interested in the conversion and more interested in the machining. However now, I wish I would had got a manual machine and CNCed it myself... Considering how much I have already changed my on 940 and how much more I plan to change, it would have made more sense to start with a manual machine for sure. Live and learn...
Don't get me wrong, the 940 is a killer machine, the travel cannot be matched which is the reason I bought it. With only changing the controller and tuning I've been able to hold ±0.002" with out really trying and I can do better than that if I take my time. Bang for insurgent U, it's tough to beat.
I was just looking at your thread about the 940 I see what you mean about all the work you are doing. It’s a shame you had to do it.
What are your plans for increasing the spindle speeds? Are to going to eliminate the gear box altogether? I always hated how loud the gears sounded on the RF45. I also upgraded my spindle bearings and installed a 3 phase motor. I ran mine as high 3000 rpm with a vfd. Talk about noise.
I have the 940-CNC-VS, so it's a VFD controlled motor with 3200rpm max speed. I'm ditching the gear box all together, it just won't be able to get to the speed that I want, and I'm tired of listening to the damn thing.
I'm going to attempt a two speed belt drive that will be controlled by the CNC controller. It'll be similar to Fadal's Pozi Drive, time will tell if it will actually work.
Basically it comes down to a 2.089:1 motor to spindle ratio (I think Jack got 2.000 on the dot). That should get us a top speed of ~7200rpm at 120hz and -600rpm at 10hz. The sweet spot for roughing will likely be about 3600rpm and 60hz. As for the dual speed belt setup, I have no details, and haven't found anything about anyone trying it. Fadal made it work, so I figure it's possible.