Steve,
Cause and Effect, no threads, stripped out.
I am particular about these things so I checked 67 AIM U17 A4 #8 606404 P. Washer and #9 3817006 Screw Asm. against my BB.
My BB has a black bolt with conical washer, so I checked AMK and they show a zinc washer with a SS 1/4-20x7/16 bolt with external lock washer.
Looks like I need to find the finish on the washer and now what is the correct bolt.
Bob