Dan,If you are talking about the ferrules on my knives fere lately The small Gentelman tacticals were easy.You just make a straight line cut all the way around the handle piece and then file aay the piece in front of the cut.Now make a blank out of wood the size of the handle only make it smaller so that the metal is the same heigth of the handle material.Now wrap a piece of the type of metal you are using around the form when you over lap the joint make a cut through both pieces with a jewlers saw or a coping saw with a metal cutting blade in it.Now silver braze the joint together,clean the solder,now check the fit on the handle and dress up the handle untill it fits tight against the shoulder you cut in don't worry if yoou get the handle material a little small inside the ferrule.Now you just fill it with epoxy when you glue on the handle,and there you go.
If you have some questions about these older styles of knives email me and I will try and help.
Bruce