Greetings fellas

I am building a single speed bicycle from a 70's Dura-Ace multispeed rear hub. I removed the Regina Extra Gold free wheel, removed the skewer and spacers and centered the hub in the existing hollow axle. The hub spins lovely but I do not know what track nuts size shall I buy for this axle. I tried Surly track nuts but they are to wide in diameter, I tried some old maillard track nuts and they are too small in diameter.
Please fellows help me on my search for the right track nuts diameter for the Dura Ace axle.

I'm making a wild guess here, but I think the problem you're experienced is this. The old Dura-Ace hub takes a 15mm nut (spanner size) but it's a different thread to the Surly, which I believe might use the same thread pattern as Campagnolo hubs. The Maillard nuts are 14mm (same as old Normandy hubs).
So I'm fairly sure you need 15mm nuts, but with a different thread to the Surlys.

That doesn't really help much does it.

Thanks oldsprinter. Not great help but some help.

Take the axle to the LBS, and they should have a tool to check the thread pitch and axle diameter. Then just buy whatever track nuts match the threading.

If it was a more modern hub, I'd guess 10x1mm for the rear axle, but I don't know the older stuff.

its probably 3/8(9.5mm)x26tpi

I read the thread tittle, and thought you were just really into dura-ace axles.