I replaced my 2-piece axles with one piece Moser axles in my AMC, but had to have the hubs removed before I sent my stock axles to Moser. I found a shop that would remove the hubs with a BIG press. Sounded like a gunshot when the hubs came off. Yikes!

So, to use the later-than-64 sure grip chuck I have, the easiest way would be to swap to a later axle, preferably a 65?