Jim Jarvis shows a very similar method but flipped - the fin is held stationary and the sanding paper is bonded to a board that is pulled across the edge. Requires careful layout but anyone who has seen his fins knows the results are extremely consistent.If you just sport fly...who cares.
Want more performance, bevel.
Very simple hand jig can be done with a couple of C-clamps, scrap wood and sandpaper. Add a bit of elbow grease and 15-20 minutes later....done.
https://www.rocketryforum.com/showt...t-seal-of-approval-build!&p=534237#post534237
Just Google 'TooCarbYen Sustainer Fin Can Rebuild.pdf' and you'll find a link to the document. The fin section starts on page 24 but the entire document is well worth reviewing.
Tony