More progress i contacted the seller and he sent a picture of the joint with a brass insert. However i knew sherm used the inserts with the ball shaped pilot. Looking closer to this pic im attaching here it looks like the pilot was trimmed off on the lathe. There are also letters here at the joint end. Was this something that Sherm put there to remind him of which cue this shaft was for? The brass insert doesn't mean much, because i have brass plugs threaded 7/16-14 that i can tap to anything. My guess is 5/16-18
I talked to Sherms son and he wasn't sure of the smaller pin size or if there were any that were different than the rest. All he could tell me, was that Sherm moved on to the radial pins
I may go see the cue measure myself then we know for sure.
ENLARGE THIS PICTURE, LOOK AT THE BRASS IS IT CUT FROM THE PIN OR A LATHE
This is a private seller Sherms son knows nothing about this cue