Edit: I thought to ask Google AI about some type of product that might help with joint pin into the super tight threads, and they recommended Beeswax, so I had this Longoni Special Way laying around, and put some of that stuff all over the joint pin, after cleaning it the best that I could. Then, I slowly tried to screw in the joint to the Mezz shaft, and at the point that I thought was stuck before, I was able to keep turning it, even though it did get super tight, and much harder to turn (as it would normally be, though tighter it felt), but I was able to screw it in all the way. I then did that about 3 times over, going back and forth, and I feel that it should be good now (hopefully). So, maybe the pin was just dirty, or the insert a little bit rusty, but not sure. I do wonder if there is a cleaner for cleaning the threads in the shaft. Thanks for your replies.

I would like to start out by saying that on many previous occasions, a Mezz United Joint shaft would fit on a standard 5/16x14 joint just fine. Like, on a Joss cue, for example. It was a very tight fight, during the last few turns, but I never had any issue putting a Mezz United Joint shaft on a regular Piloted 5/16x14 butt, that was not made by Mezz.

For the 1st time ever, I am experiencing a Mezz United Joint shaft that is is getting stuck, about 3/4 of the way down, and will not turn any further, on a regular 5/16x14 Piloted Joint pin.

Any ideas on why this is happening? Have you ever experienced this issue, when trying to put a United Joint Mezz shaft, on a regular Piloted 5/16x14 joint pin butt, that was not made by Mezz?

About 3/4 of the way into screwing the shaft in, it really feels that it does not want to go any further, so I did not want to try to screw it any further, for fear of it really getting stuck (lol), to the point where I would be unable to unscrew it. Also, please keep in mind that I am very weak, if that makes a difference, lol. I just really did not want it to get stuck.

This is the 1st time I have ever had this issue though, with other United Joint Mezz shafts. The last few turns were always pretty tight turns, but nothing that felt like it might get stuck, if that makes sense.

Maybe this shaft is just defective? I do not know. I assume it would probably fit fine on a Mezz United Joint butt though, but I honestly do not know.

Anyways, thanks a lot for any thoughts.