I can understand the need to know where it went. I had a bolt that secures the tank on my old 600Fazer go MIA one ride - thought it probably bounced down the road. 3 Months later, changing spark plugs, when I blew the dirt and gunk out of the plug-well prior to loosening the plug, lo and behold, up floats the 6mm bolt on a cushion of air!
I can only wince at the thought of not blowing the gunk out, removing the plug and letting the 6mm bolt fall onto the piston. Great that you found it!
And a good story about the 18mm Craftsman.