a regular 5/16x14 piloted cue wont be able to fit on the Mezz United Joint. I tried fitting a regular 5/16x14 piloted OB-2 on my Mezz, and it didnt go through fully, a few threads remained. The pin insert on the shaft might need a slight pass of 21/64" or even 11/32" diameter for about half an inch into the insert maybe. Royce from OB cues might know more, or even Mezz USA could answer.
I've thrown a joss shaft on my mezz without a problem.
Just wondering what size pin would fit for united joint and if it needs to be piloted, cant find definitive info on ob website... Any help appreciated.