I have a spare joint protector, the male portion, that goes into the shaft end, and I think it is a radial. It works fine, but I need the butt and protector as well. It's just a bit difficult for me to identify this single piece that I have as to what type of thread it actually is. Here is a picture of the butt end to identify?Have you tried using regular radial joint protectors.
The only problem with that is I lost the female portion and can't find it. So I have to buy a new set. I have it on order, from amazon, so I hope it's the right one.It looks like its a knock off radial. But if the male jp fits in the shaft then the female jp should fit as well.