Someone please check it for me, but here is how I did the calculation...Michael (Swampwalker), thanks for (as usual) bringing some level-headed and intelligent perspective to this thread, as was evident in the conclusions you stated in your earlier post. But upon checking your math I see what appear to be a couple of incorrect calculations.
75 square micrometers/square microns = 1.16E-7 square inches.
1.8 gm = 0.0635 ounces (not pounds) = 0.00397 pounds.
0.00397 pounds/1.16E-7 square inches = 34224 psi, much higher than even you had calculated.
Although offhand I'm not totally certain that the 75 square micrometers is really that, or if it should be 75 micrometers squared = 5625 square micrometers, which corresponds to the square inch figure you used, and which would put the psi just slightly higher than what Tony had indicated. Can anyone else confirm that (as I suspect) 75 square micrometers is a reasonable figure for contact area?
Also, without doing further research I too have no knowledge of how to convert that to a temperature rise, or if Tony's assumption of a 0.22 coefficient of friction is accurate. FWIW, though, I recall that some time ago an article by Robert Harley in TAS cited the same 500 degree figure that was mentioned above by Vetterone.
Best regards,
-- Al