Brief Description: Milling the control column mounts
The idea of attacking the control mounts with a hacksaw and file filled me with horror. I am fairly confident on convex parts but that inner cut would be sure to give me problems. Fortunately, RV-7A builder Phil Cobbin has a Bridgeport and his own computer control system for it in his hangar. In exchange for a little stick time in my RV-6A, he agreed to mill the parts for me including drilling the #12 holes. He set both parts back to back in the machine and carefully set the zero coordinate at the top between the two pieces. It was then just a matter of entering the path coordinates for the tool and letting it mill a few thousandths at a time. After many passes, the cutouts were done and then he changed to a pilot drill to start the #12 holes, followed by the final bit and a quick pass at deburring. I radiused the outside corners with a file and broke the edges lightly on a scotch-brite wheel to finish.
