Is there any reason a 2006 Volpe fork couldn't be installed on a 2009 Volpe?

before is 1" threaded but now every thing is 1.125" threadless?

Both forks would have 1 1/8 inch threadless steerers, so you should be able to make the swap as long as the steerer tube is long enough. If you take a fork from a small-framed bike and try to use it with a large frame, the fork's steerer tube may not reach all the way through the frame's head tube.

Why ? you damage the other one?

No damage on either fork. Both are threadless.

I'm thinking about taking the fork from a 2009 55cm frame and swapping it with the fork from a 2006 58cm frame.

Why? The 2006 has mid-fork braze-ons and the 2009 does not. I'd like to keep the 2009 55cm bike. While I don't have both bikes in front of me, I'm guessing the headtube on the 58cm frame is about 1 inch taller than the headtube on the 55cm frame. Sounds like it may not work..

Some data:
Volpe | Bianchi USA

Well, it would work for the bike with the smaller frame. There's a good chance the fork from the 55cm frame won't work for the bigger bike. It depends on the difference in the frames' head tube lengths and how short that fork's steerer was cut.

It'll work. The longer steerer tube will either require some spacers, which will allow you to really dial in your handlebar height, or the steerer tube trimmed to fit.

Brad

I'd guess the 58cm frame-fork will fit in the 55cm frame, but I want both bikes to be usable. Actually, after the swap, the 58cm bike (with the 55cm frame-fork) would be sold & I'd keep the 55cm bike (that would have the 58cm frame-fork installed)

You can buy a new cantilever fork with mid-blade braze-ons for around $90. Cheaper if you get a used one.
eg:
Pake C'Mute 1 1/8" Threadless Grey, Unicrown Fork
Surly Cross Check Fork 700c 1-1/8" Threadless w/ Mid-blade Eyelets Black

I've put a 2013 Volpe fork on a 2007 Volpe, a 2015 fork on a 2013 Volpe, and a 2015 Volpe fork on a Cannondale T2 (almost identical forks). They all worked fine and were done to utilize uncut steerer tubes to facilitate fit.

2015 fork on a 2013. The mid-fork braze ons were a bonus. I don't think you'll have any problems.

Good info..thanks guys.

Doug64..you are a Volpe-king. I ran across a photo of yours like the one above, though the Volpe was a Gang Green model. You must have a collection. I did my first ride on a new-to-me Volpe yesterday..36 miles..nice ride. I can see why people like this bike.