Mill / CNC Conversion

Conversion of the RF30 to CNC was not an easy task for me. Originally, I wanted to make circuit boards without the use of chemicals. This is a process called “isolation routing” where a very small router bit cutter goes around the traces of the copper to isolate that trace. The board is then drilled and removed for soldering.

When I started this project in 2012, I received a lot of bad advice from a close family friend, a machinist of over 50 years, who I thought knew better. 6.5 years later, the build is nearly complete but I still haven’t produced a single circuit board, and in that time, China has popped up and able to send me PCBs for next to nothing. I’ve since changed hobbies though into mechanical design and machining: which is lucky as I wouldn’t have much use for a lathe and half-built milling machine any other way.

Based on bad advice, I was told to use tapered roller bearings, and machine the ballscrews myself. After a friend offered to machine them for me at the university machine shop, and we were kicked out and reprimanded for it, I decided the only thing to do was to buy a lathe, learn to run it, and then build parts for robots to compete against the very forces who conspired against us!

Machining ballscrews as a n00b to a lathe is something I would not recommend. It is difficult enough setting a threaded item up in a 4 jaw chuck such that there is no runout, and incredibly difficult to measure the runout accurately if the lathe cannot match the pitch of the screw. A few years later, I bought a 5C collet chuck, and re-machined the screws, and it was easy as pie, possibly owing to the fact I was also using carbide now and had a better grasp of feeds and speeds for materials.

The driven ends of the ballscrews are machined to take two 30202 tapered roller bearings (15mm diameter), and preloaded with an M14x1 nut. The screws are driven by a pulley that was reamed to 10mm.