guzzialfa The problem is a regular "shoulder" bolt has a much longer shoulder. You have no choice but to custom make one like I did. Her is some good information: www.ondrivesus.com/shoulder-screw-grades-dimensions-materials-and-options
Just a thought, try the 8-32 x 5/8" long SHCS but as you tighten them down go half a turn on each side until tightened down. That should keep the ring from binding against the threads. Worth a try.
