Grafiko,
at first blush I was included to describe and draw the adjustable Cinqowrench (five-sided AN-346-T specialist aviation tool) before posting it on this forum. That's what I love about this site - experts galore. The right answer is, no, I have never seen a five-sided nut, and they probably dont exist. BUT, they shore look good on my wheel!
At this stage I like to think that GFR's flat nuts are more contorversial!
Mclaring