Slightly over 4,000 pieces of these custom captive shoulder screws were made domestically for our aerospace customer. An MS24671-32 part made using 302HQ DFARS compliant material was used as a base part to create this final version. Part of the 1/4-20 3A thread was turned down to a shoulder diameter of .175″ +/-.005 and length of .339″ +/- .015. .375″ of thread remained after the modification. The resulting captive shoulder screws were then passivated per AMS QQ-P-35 and run through a thread lock patch process per MIL-F-18240.
Although the parts look relatively simple, some of the modification processes were very difficult to incorporate correctly. When the shoulder area was turned down to create the shoulder it became apparent that every screw had to get the thread chased one at a time – a very cumbersome and time consuming process. Parts were provided to our customer with full certs and our internal part number is 6658788-1.