Quote Originally Posted by Brandon77
Heh, how do you do that? Hinge a weight to your jaw and open/close your mouth? :P I think you're talking about the term "glassjaw", the jaw itself doesn't have much to do with KO resistance (though the chin is the 'magic button' where nerve endings are bunched together). Stick with the neck exercises listed by Ross Enamait, he is very knowledgable and I can vouch for their effectiveness.
I believe Mr. Marciano used to chew really tough meat for hours...someone back me up?