Got out my reamers to clean up every hole on the fuselage. Tubing will distort when welded, so expect to clean up every hole.AN3 -- 3/16" reamerAN4 -- 1/4" reamerAN5 -- 5/16" reamer.A drill has a habit of making a "figure 8" out of a hole. With a reamer, drop of cutting oil,and twisting by hand... nice perfect diameter hole.Some of the tubing (i.e. engine mount) will have more distortion, so clean up with an undersized drill first (that 7/16" hole caught me off guard, snapping a drill bit in two), then with the reamer. I've done only the drilling for now, reaming will be a "match ream" when I have the engine mount (engine is tbd).The fun part was drilling ( I and Q drill bits, please) then tapping the rear seat mounts. 5/16"-24and 3/8" - 24. Lots of cutting oil. Take your time starting. Turn 1/2, back 1/4.... welded (i.e. heat treated) 4130 doesn't tap that easily. Thankfully few tapped holes to deal with.
