Thanks everyone for the replies. There's a little over 3/4 of an inch sticking out, and I think I count 9 in half an inch (thanks KJ). It looks like there are more threads in this pin than there are in the 14 example from CueCaps, so I think that must be right.
I was a bit concerned that this cheap Chinese-made, English-branded cue might use a non-standard joint. I'm looking for a 12mm shaft, regular deflection. $150 or less with delivery would be good. I'll post in the wanted section, just saying in case any of you guys has any shafts lying around!
Thanks again!