As with anything, budget was a concern, and any money I can save on the conversion is money I can spend on stock and upgrades. I know its a HF mill so my expectations of it aren't super high. I know I won't be making parts accurate to .0005". If I can hold .003" or better, I will be pleased.
For the controller, I am running linux CNC on an oldish computer my boss and I built from spare parts when I was an intern at my company. It isn't a workhorse computer, but it seems to be good enough. I found an old mac keyboard tucked away in my parents attic and snagged an old 19" monitor from work. I also gutted a very old (Probably around 2000) computer to use the case to house the CNC electronics.
For the motion, I am using 400 oz in Nema 23 motors on all 3 axes, TB6600 drivers, and a 7.3A 48V power supply. I got an el cheapo break out board for about $10 on ebay to interface the computer with the drivers. It is optoisolated, is powered by USB, and communicates with the parallel port.
I ordered some 1605 ball screws on ebay for $160 for all 3 axes and got them installed. I haven't measured the backlash correctly yet, but when I use the DTI and order a .001" movement in the opposite direction, the DTI indicates .001" movement. At the very least, it should be close to 0 backlash. I am using thrust bearings in the X and Y axis, and 2 "angular contact" bearings for the Z axis. I have the X and Y mounted, wired, and moving, and I am working on fabricating the Z axis at the moment.
The ball nut took away some movement in the Y axis. I am getting right around 3.9 inches now. I will break out the grinder and remove some material from the base to get that back. I should be able to get to 4.75 easily, maybe 5 if I really push it. The X is getting 9.75 without overtraveling the ways, and maybe 10.5" while overtraveling one direction safely. When I finish the Z, I should gain 1.5" of travel at the top.
The X and Y have no trouble rapiding at 108 IPM, and when setting up, it was able to get to 5 inches/sec (300 IPM) before it started to stall, but it didn't seem to be going that fast. I may have been losing steps at some point. Though 100 IPM is plenty for me.
I still have a good bit of work to do, and I will have a lot of questions. I am going to do the hoss pneumatic tool changer once I finish the Z axis and I got a 1.5"x36" piece of 4140 for christmas to make a bunch of tool holders.
Here is what I have done so far.
Here are the parts I have made for the Z axis so far.
Here is the whole set up on the bench.
This video shows the X and Y axis motion.
Here is a facing cut in 6061 aluminum at 60 IPM and .003" depth of cut.
Here is another cut, roughly .5" deep at I think .01" wide. Please pardon the overlay and the vertical video.
Im happy to answer and questions and I am open to tips and suggestions if anyone has them.