Looks like a valve build might be able to happen this weekend! We are pumped to get the Ion firing more effectively. As long as I can get to work on some design we should be able to turn it out this coming weekend!
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The most recent success in my ongoing RF-45 mill repair project is the fabrication of a new Y-Axis lead nut. The stock nut was apparently lost somewhere along the way during the attempted CNC conversion that I’m partially reversing, so I had to come up with a replacement.
My first thought at replacing the nut was to make a new one out of acetal plastic based on the method described at the Home Shop Machinist Forum. On second thought, I decided it would be much more practical to see if I could find a replacement part online. Like many of the chinese machine tools out there, this mill is one of many clones of an original design. In this case, the Rong-Fu 45 is the original, and my copy was produced by Penn Tools. Unfortunately, I was unable to find replacement parts through them, but Grizzly sells a similar mill along with replacement parts. I dug through the manual to find the part number, contacted Grizzly, and ordered the nut. Easy enough right?
Unfortunately, the importer of my mill chose to use 8 TPI leadscrews, while the Grizzly version uses 10 TPI leadscrews, so the nut didn’t work. I returned it to Grizzly, and set off on my original plan of making the nut from scratch.
I started by boring and splitting the acetal to fit the lead screw:
The RF-45 mill I purchased on craigslist a few months ago had some issues… In an attempt to convert the mill to CNC using an extremely oversized ballscrew, a previous owner had milled a pocket out of the bottom of the bed, leaving the material below the bottom of the center T slot uncomfortably thin. With the goal of restoring some of the bed’s original stiffness, I’ve fit a steel plate into the pocket. This post documents the process of machining the plate to fit the bed.
Here’s the bed as it stood before adding the plate:
A few weeks ago, my Craigslist RSS feed returned a listing for a mill for $300 only a half hour from my house. It was an RF-45 clone that the seller described as a “project.” The RF-45 is a much more substantial mill than the X2 mini mill I currently have, so I was intrigued to say the least. After a bit of thought and contemplating if I had room in the garage, I decided to give it a shot and contact the seller to get some more info.
It turned out that the previous owner had begun a CNC conversion on it, and in the process had milled a large pocket under the table in an attempt to fit a much too large ballscrew on the X axis. The mill was disassembled, but all the stock leadscrews and handwheels were included, except for the Y axis acme nut. The seller had intended to finish the CNC conversion that the previous owner had so poorly started, but never got around to it since he already had another CNC set up in his garage. Fortunately, he held on to all the parts necessary to run the mill manually. I’m not quite ready to jump into the world of DIY CNC just yet :-).
All in all, it seemed like a pretty good deal, so I arranged to pick it up the next day. Now I had to figure out how to move it. 700 pounds of chinese cast iron doesn’t just jump in the back of a truck…