Sourcing vintage TA crank bolts

In short I’ve managed to shear a chainring bolt on a 1976 TA 3-bolt crank and I’m having trouble sourcing a replacement. It’s a 9mm external diameter on the nut and 12mm external diameter on the outer flanges. Can anyone suggest what this particular measurement is called if anything or what I should search for and where?

Perhaps email Velo-orange see if they stock or know of any that may be available. Otherwise BNA has a retro bike area in their forum that might be able to help.

Unfortunately the 3 arms are no longer very common, ebay has heaps of PRO Vis 5 bolts but but non of this style?

If you dont mind it looking a little crummy for awhile french bikes use metric threads, it might be possible to just use a standard 10mm metric nut?

Hilary Stone?

Rene Herse?

Hilary is a good bet … but not the first place I’d try.

Work out what the small part name or ref. # of the part is … should be somewhere in here.

Specialites T.A. - pro 3 attaches chainwheels
Specialites T.A.

eBay should be the best/cheapest bet but not everyone who sells stuff knows or understands the minutia or tricky details between the years, so be careful and ask all the questions if the seller doesn’t make it clear/obvious.

For that reason I’d check with Ralph of Via Bikes/Bikeville who is an excellent dealer and knowledgeable with this kind of small or obscure stuff.
Cranks and Chainrings

Long shot, but it may also be worth checking with Wayne Bingham … who took over Mel Pinto Imports (Var tools, and a lot of French small parts) and also owns Velo Classique.
Mel Pinto Imports
Velo Classique

At a guess I don’t think I have any of the size chainring bolts that you need and won’t be able to check until later next week (long shot at best).

Thanks for the help - I’ll start killing my lunch breaks tracking one down this week!

Hey not sure if this is the same, sorry to add to an old thread but thought you might be interested

Bit of a bump. Did you get it sorted? This seller has some TA bolts:

hunterbc | eBay

Two chainrings on three arms:

TA T.A. accouplage couple 3 attaches ref. 43 2 rings 3 arms NOS | eBay