I don't actually remember at what point I became interested in converting my RF40 to CNC, but apparently it seemed like a good idea to me at the time. I guess a large part of my interest in CNC is I'm mostly a computer programmer, so computer control just seems natural.. In designing the CNC conversion, I wanted to retain manual control of the milling machine and I wanted to make a conversion that did not require any modification of the machine itself. I think I met those goals pretty well.

IMG_6071.jpg I made a pretty simple frame out of 4 3/4" posts, drilled and tapped on one end and are turned down on the other end to fit in a locating hole. IMG_6073.jpg The turned down end is a slight interference fit in the hole in the plate.
IMG_6074.jpg All of the pieces were made on the mill.. Getting the posts to the correct height (they're all the same within a few tenths) was a little interesting. I was really pissed when I broke a tap in one and had to make another! IMG_6072.jpg Once I had everything together and I checked that everything was square, I welded the non-tapped ends to the plates. It would have been nicer to use bolts but then I would have had to drill clearance holes in the mill and the motor to clear the bolts heads which wouldn't have been nice!
IMG_6160.jpg I used a cheap Lovejoy coupler because I couldn't find anything better that could be used with the 17mm lead screw shaft. I shimmed the spider so there is zero backlash. IMG_6162.jpg In retrospect, I probably should have welded both ends as I didn't need to be able to dissasemble the frame in order to attach/remove it from the mill/motor.
IMG_6257.jpg Because I wanted to retain the use of the handles, I wouldn't be able to use a direct drive on the Y-axis. Instead I designed a bracket that would use pulleys in a 1:1 ratio. Because I'm too cheap to buy layout dye, I used a Sharpie to give contrast to my layout lines.
IMG_6282.jpg IMG_6258.jpg
IMG_6259.jpg IMG_6260.jpg Because the bores need to match up precisely, and I don't have a DRO, I drilled some locating holes and then bolted the three pieces together.
IMG_6263.jpg I then drilled out the four holes that attach the bearing housing to the main assembly. IMG_6156.jpg On the Y-Axis, I'm actually replacing the stock bearing housing. Whereas on the X, I just displaced it slightly.
IMG_6266.jpg With the backing plate and the front bearing housing bolted together, I bored out the bearing holes. I didn't have a boring bar so I used an end-mill in a boring head. IMG_6287.jpg
IMG_6285.jpg IMG_6336.jpg All anodized and ready for assembly. See my page on anodizing for details.
IMG_6283.jpg My helper says she's ready! IMG_6151.jpg My first attempt and using inexpensive capacitors ended up spewing capacitor juice all over the place.
IMG_6455.jpg With a real cap, everything works great! I'm using an AC light rheostat to control speed right now.. IMG_6254.jpg Here's the computer with the Gecko cage
IMG_6456.jpg The light rheostat works pretty well, except it won't go low enough to drive the servos at a suitable slow speed. But it certainly is nice on traversal! IMG_6458.jpg

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