The Campagnolo front hub axle, part #19, remained longer than any other part that I can think of without changes. You could in fact take a 30's Campagnolo axle and fit it into a 90's hub.
The only truly rare variation that I have ever seen of the front axle was one with the radiating globe logo. I have only seen it used in the late 50's. Has anybody else ever seen an axle with this logo?
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Steven Maasland
Moorestown, NJ