Is it possible to install a threaded fork on a Gazzetta? My LBS told me that the frame isn't compatible and I'm not sure what that means. If I replace the headset with a threaded one and get the right size steerer tube, why wouldn't I be able to do it? Am I missing something?

What is a gazetta? And what's your thinking going threaded?

Outside of the near impossibility of finding a threaded 1 1/8" road fork (if this frame even IS 1 1/8"), I'd say the LBS if full of it. Guess you could thread a steel 1 1/8" steerer, but you still have the location issue.

EDIT: if it's a 1 1/8", you could use this to open yourself up to the world of 1" threaded forks.

If the headtube accepts a "standard" press-in style headset then you could use a threaded headset and fork and, yes, there were 1-1/8" threaded headsets and forks. They weren't all that common but were made.

If the headtube takes an "integrated" headset, you probably are stuck using a threadless fork.

Maybe this?
https://www.cinelli.it/scripts/prodot...=EN&IdBici=581

If that's the OP's bike it does indeed have a press-in cup 1-1/8" threadless headset so a threaded replacement headset and fork are possible. Not easy to find but possible.

Anyway, here are a couple of 1-1/8" threaded headsets:

https://www.loosescrews.com/index.cgi...id=67644823940

Item 3 is a Ritchey and Item 6 is a Shimano.

Sorry folks, yes it's the Cinelli Gazzetta and is 1 1/8". So I would need a 1 1/8 threaded headset and fork? Why would the LBS say its not possible?

https://www.cinelli-usa.com/framesets/gazzetta

Probably because he doesn't want to bother sourcing the parts and thinks the conversion cost would be more than you would accept after all of that work. BTW, what is your incentive for the change?

Two reasons: I personally did them easier to adjust and replace and aesthetically they look better, especially on a classic style frame like that.

Nice to know someone out there actually prefers quill stems. Being able to adjust the headset with an allen key was enough to get me to jettison the threads. I also like my stems low, so the lack of height adjustment doesn't bother me.

There was a time when 1 1/8" threaded headsets were pretty common, I know my ancient trek came with one.

Mine too. I had a '93 Trek 7000 set up with a 1-1/8" threaded headset, fork and quill stem.