DrHotdogs3

darkhorse75

Check out this thread hub threading,freewheel threading

Andrew R Stewart 

Yes. Campy has made hubs with various threadings that are relatively standard. Italian (35mm x 24TPI), French (34.7 x 1mmPT) and the most common Eng (1.370" x 24TPI. These days the ISO thread standard is what most hubs are made to (1.375" x 24TPI). Some Campy hubs have the threading stamped on them. Itl, Eng and ISO are class B fits but it's not recommended to go back and forth between the different thteadings. French is not interchangeable with any of the others.

A number of freewheel brands all had their freewheels made with the various threadings. Some brands have indications (stamped labels, machined rings in faces and punch marks) which tell the hub's threading.. So can you describe the hub's threads and/or any shoulder markings? Maybe a photo of this detail? Was there a freewheel and do you still have it? If so a shot of it's backside and it's brand might help.

I suspect you have an Itl or Eng threaded hub but you need to make sure. If nothing else you could test fit known freewheels. Andy

JohnDThompson 

First, you need to determine what thread spec your hub has. As Andy suggests, it's most likely English or Italian, but you need to be certain. Campagnolo marked its hubs to indicate thread spec:


Source: Sutherland's 4th Edition

Any freewheel with matching thread spec will fit on the hub, but you should also determine how many sprockets will fit without clearance problems. For that, you need to determine the "over locknut distance" ("OLD"); that is, the distance from the face of one locknut, through the axle to the face of the other locknut. A 1960s bicycle is likely to use 120mm to 126mm OLD. If your hub measures 120mm, a 5-speed or "Ultra-6" speed freewheel will work. If 126mm, up to a 7-speed freewheel will work.

fietsbob

Export hub is probably British thread..

Campagnolo did make freewheels .. expensive light and alloy cogs wore fast ..







...

JohnDThompson 

And a proprietary remover, of course. Many of the Campagnolo freewheels you see on the used market have their remover slots trashed from using the wrong tool.

fietsbob

I recall seeing that , from afar, a CCW angled version of the type of remover that Regina used, which I presume was done to have tool tighten itself more
in the 2 removal slots as you applied force..





...

JohnDThompson 

Campagnolo's official tool was jaw-droppingly expensive. Bicycle Research came out with an affordable version, but even that is hard to find these days.



Why Campagnolo didn't use a proven, existing design like the thin-wall splined tool used by Atom, Regina, Zeus, Everest, etc. is a mystery.

SurferRosa

Yes, pretty much all of them, including new models from sunrace and IRD.

If the hub is italian thread, go with a standard/english freewheel.

DrHotdogs3

DrHotdogs3

DrHotdogs3

JohnDThompson 

Well, 1.370 x 24tpi means you have an English thread hub. The hub appears to be much newer than the frame, as the explicit thread spec marking wasn't used until the late 1970s. Prior to that, presence or absence or an inscribed ring in the space between the freewheel threads was used to indicate thread spec.

SurferRosa

I've never had the pleasure of owning a Legnano, but that seat cluster worries me. Do you already have the correct seatpost and seatpost binder bolt?

DrHotdogs3

Andrew R Stewart 

Be aware that this type of post binder tend to place fairly high force/pressure on a small area of the seat post. You'll not want to use a very thin walled AL or carbon post. Andy