dcharles,
Most bolting used in the process chmical industry is between 5/8" and 1" diameter. XYLAN, as mentioned above, is good stuff...
"Studs" (non-headed lengths of threaded stock) with double nuts on either end are frequently used in mecanical joints simply because if one end jams, chances are good that the other can be loosened.
I would search the net (use GOOGLE, the best there is...)and use "galling" and "threaded" as keywords..
Good luck and report back to us of anything interesting
Visit the "Bolt, Rivet and Weld" discussion group on this website also..
MJC