Joe shelton
I decided to try peening. Not knowing how to do it right, I started with a center punch, then tapped until I could tell I'd moved some metal. That snugged the loose handle nicely, and knocked the other one a little loose, so it got peened.

But now two ferrules were loose. I thought that might be a trivial matter, so sharpened it and went to the shave horse, where it had a distinct preference for bevel down work. And the ferrules were a nuisance. So I mixed a little epoxy and very carefully worked it into the ferrule slots.

Appreciate everyone's help, 'specially Jack's injunction to try peening.