Thanks for all the input. So what I'm gathering from those who weighed in is that 4130 is overkill and 1018 or maybe a 1020 (A36 MOD) would be strong enough.
P.S. To Tmoose: Yes, I am trying to replicate one just like the front three in your photo. My apologies for not responding sooner.
The pre-'46 hubs are one piece. The '46 and later one are made of several pieces similar to a Harley. I don't think the vendors have the earlier version available. Plus I want to install a modern bearing rather than go with the loose rollers.
The originals were made from a steel casting. Because of the age and rarity it is hard to find one let alone one that is in good condition. My goal is to make a close copy that'll be safe to ride and use modern bearings but that's for another post.
