Originally Posted by
headasunder
measure the shell width, 68mm english, 70mm is italian
Not necessarily true. Over the years, I've encountered Italian thread shells with widths ranging from 65mm to 70mm. Italian track frames from the 60s are particularly likely to have a narrow shell and Italian thread cups. That, and stripped English or metric thread shells may be reamed and tapped for Italian threads.
A far more reliable test is to measure the inside diameter of the threads: 36mm is Italian, and an English or metric thread cup will drop inside without even enaging the threads.
And a 68mm wide shell could also be metric (35 x 1) thread. Metric thread was not limited to France; Spanish built frames such as Zeus (Orbea's predecessor) often used metric thread.