A little help.

[RAMBOCAT]

Does anyone out there know of a way to make leather washers permanently expand? I have a knife my dad made during WWII and the washers have gotten loose. i'm afraid if I put any more torque on the nut, i'll break the tang. And yes I've put every brand of penetrating oil on the nut. it's rusted solid.

 

[PoolQs]

I don't know if this will help you but will educate you on the makings of a leather handle. I know a couple of makers that swear by this method.
Maybe you can incorporate some of this to repair yours; Leather handled knife tutorial
Best of luck !!