These custom captive shoulder screws were manufactured using a modification to a COTS part for our defense customer using 18-8 stainless steel material with standard 2-56 3A thread and standard socket head dimensions.  Length underneath the head was designed to .750" +/- .005" and the shoulder was turned to a diameter of .052-.054", at a length of .066" +/- .005".  The thread had to be chased for each part to ensure smooth thread transitions after the additional shoulder was incorporated.