> Those pins were from the early-mid 90's. Those,along with the current/original form are actually a tad undersized across the top and at the bottom of the thread (major and minor diameter) groove. Instead of being a true 5/16 which in decimal form is .3125,the Schon comes in at around .302. This makes it easy to find aftermarket shafts such as the Predator,and be assured of it fitting. Evan and Bob's reason for this was the opposite,however. Without the tap,you simply cannot make a Schon shaft fit a Joss or Falcon butt,it will completely seize. Schon shafts are typically pretty snug fitting for a brass insert even with the undersized pin,their logic was this made it harder for other cuemakers to reproduce their "hit",as well as cut them out of replacement shaft sales.
My Runde-era has the original style,threaded all the way to the end,and chamfered. I made some joint protector pins recently that kinda look like the one shown by the OP. Tommy D.