Bicycle Mechanics - Front Derailleur Follies

I searched the forums but didn't find an answer. I already have a Dura-Ace FD with a 28.6 clamp that has been sitting around for a while. I need to put a FD on my Ghisallo frameset, but the seat tube diameter measures 34.9, and since Shimano does not make a clamp on this size, I understand that they recommend buying a braze-on + a FD adapter clamp that fits a 34.9. But before I go and buy a new derailleur, is there anyway that the clamps can interchange i.e. get an adapter clamp and use it on the Dura-Ace FD I already have? Or are clamp-on FD's fixed and non-interchangeable? Probably a dumb question, but I did my first century yesterday and now my brain doesn't work :o

I searched the forums but didn't find an answer. I already have a Dura-Ace FD with a 28.6 clamp that has been sitting around for a while. I need to put a FD on my Ghisallo frameset, but the seat tube diameter measures 34.9, and since Shimano does not make a clamp on this size, I understand that they recommend buying a braze-on + a FD adapter clamp that fits a 34.9. But before I go and buy a new derailleur, is there anyway that the clamps can interchange i.e. get an adapter clamp and use it on the Dura-Ace FD I already have? Or are clamp-on FD's fixed and non-interchangeable? Probably a dumb question, but I did my first century yesterday and now my brain doesn't work :o You can't use what you have. A true clamp or band type shimano FD has the clamp fixed.

35.0 is a fat seat tube! I don't know about Dura-Ace but Shimano does make a 35.0 front derailleur clamp that works with braze-on mount derailleurs. My Ultegra derailleurs will bolt right up.