I stepped my mast down to service the shrouds and looked at teh heal of the mast. A stainless steel disk is riveted to the base.When the mast is pulled up it will eventually sit on the ball. The top of the aluminum ball had a small stainless washer that fell of (about the size of a dime). Is this usually a riveted washer or a special disk of some type? Im not sure how it sits on the ball without spinning. i would have expected a teflon disk. Would it be better to tap a flat headed SS bolt into the top of the ball then grind it flat? Has anyone had to repair this before?