I once saw mention of a RAM ball with a stud that's the same thread as a dashboard screw. I looked around and the closest thing that I could find was a RAM 1" ball with a 1/4-20 female thread. That's close enough to the dash screw's M6-1.0 to be chased with a M6-1.0 tap and serve the purpose. Got a long-threaded M6 machine screw and with the head in a vise, screwed the freshly-tapped RAM ball firmly onto it. Sawed off the protruding stud to about the same length as the original dash screw and Bob's your uncle. The Garmin that I'm using doesn't have a 1" socket, so I found a 17mm ball adapter for the Garmin. It kept facing the floor until I treated the ball with some rosin that I had lying around for treating the strap on a strap wrench. That provided enough friction for the Garmin to stay pointed toward me.
Balldouble socketball adapterI was afraid that the suction cup mount might eventually suck a bulge in the aluminum. With the above scheme, it's a simple matter to restore the original dash screw. Perhaps not the cheapest solution, but reasonable enough.
John
