I use a hard steel grade 8 washer with a big enough inside diameter for the shoulder section to pass through, and thick enough to let the nut tighten without bottoming out on the shoulder. The washer allows the proper clamping force to be applied, and the very snug fit in the hole positively prevents any relative motion between the pieces.

"One convinced against his will is of the same opinion still!" Kevin simply refuses to be swayed in his insistence on doing thing his way.
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!