With an air cooled cylinder barrel is it best to "shape" (non-circular) the outer profile of the fins first, before cutting the fins or the other way around (cut the fins then profile the outer edge)? Bear in mind I only only use HSS tool bits and shaping could mean filing by hand (no milling machine!). I want to change the outward appearance of the head and barrel of an Upshur Twin.
When I have made engines with fins I shape the block and turn or saw cut the fins as the last operation. The fins are rather easy to damage or bend by secondary operations. David Kerzel