I don't see why you couldn't still CnC them out? Make a full-sized template of each rib, (Out of inexpensive 1/8" plywood.), then scan it into your system. Where I used to work (I am now retired.), we had two large CnC machines (I did not operate them.). There was also a scanning station as well. An operator could take a plywood pattern, trace around it with a digitizing "pen", and the object was scanned into the CnC's computer system. Whether you make a pattern for a router, like I did, or make a pattern for scanning into a CnC, a pattern needs to be made.

Any carbide tipped bit will cut aluminum. I have even cut 1/4" thick aluminum on a tablesaw; using a carbide tipped saw blade. I used a carbide tipped, double fluted, straight bit. What I can't remember is, if it was a 1/4" shank, or 1/2" shank. My guess is (Without watching the video.), it was a 1/2" diameter shank.

@@BlackLabAdventures I’m building a Thatcher CX7 and just trying to figure how everyone is making their ribs

@@tazinator0418 I know what I shared in my video was an eye opener to many. At the time that I did this, the only videos out there were of people hand-cutting their ribs out with shears, then filing them back to a drawn line. "I don't have time to mess around with that!", I said to myself! Use a router like I did.