Bicycle Mechanics - Parts transplant

Hey folks I need advice on some parts I'm transplanting from an '02 bianchi eros to a 1983 trek 630. The rear derailleur went on fine, had to get a second front brake for the rear due to bolt length problems (brake bridge looked a little narrow to ream out), bb and cranks o.k. The only real sticker is the f. derailleur. See I had the frame powder coated. Did that add enough to the dia. to screw the deal. The seat tubes for the trek have inside diameter of 27.2 The don't know what the outside dia. is. The clamp for the f. derailleur is 28.6mm. It just doesn't quite want to go all the way around the tube. I could possibly use a longer bolt on the clamp, though it might ding the paint job. Is that realistic or do I need a different fd. Thanx.

Hey folks I need advice on some parts I'm transplanting from an '02 bianchi eros to a 1983 trek 630. The rear derailleur went on fine, had to get a second front brake for the rear due to bolt length problems (brake bridge looked a little narrow to ream out), bb and cranks o.k. The only real sticker is the f. derailleur. See I had the frame powder coated. Did that add enough to the dia. to screw the deal. The seat tubes for the trek have inside diameter of 27.2 The don't know what the outside dia. is. The clamp for the f. derailleur is 28.6mm. It just doesn't quite want to go all the way around the tube. I could possibly use a longer bolt on the clamp, though it might ding the paint job. Is that realistic or do I need a different fd. Thanx.
The nominal OD of your Trek's seat tube is 28.6mm. You'll have a tough time finding one larger than that without going to something egregiously oversized.

I suspect you'll either have to put up with a ding in the powder coating or ream the present FD slightly to fit better.

N.B. Once reamed, that FD is unlikely to work on any other frame.