Could you use your mill during the build. Or would you suggest having another mill if work needs to be done and keep it off to the side as a project?
I guess that depends on how you're doing the build. Are you converting a RF30/clone using Paul's kit like I did? If so, the down time is minimal and no need to make any parts on the mill. That and the cost was the biggest reason I went with Paul's kit. Now, I had to tweak a few things due to me ordering the wrong size and a couple of other self-inflicted issues. However, if you order the correct parts you just remove the handles and bolt on the motors (10-15 mins per axis). If you're doing your own electronics as opposed to getting those from Paul too then that might take a little more time but if that's the case I'd do those first, then bolt on the mechanical parts. If you get the whole kit from Paul I'm sure it can all be done in a day (or worse case one weekend) with a little planning ahead (more on the controller/electronics/PC side).