Board Thread:Questions and answers/@comment-45656015-20200501102944/@comment-27306930-20200501161051

I have had this very same problem. The nubs (aka blocks) in the priming handle are notoriously weak. I have not seen 3D print files for replacement handles, which is surprising considering how often this problem occurs. I have fixed this problem by cutting small blocks of plastic from the shells of dead blasters and epoxy welding them to the priming handle. Basically, I rebuilt new nubs. No one ever sees it, so it doesn't have to look pretty. And I made the new ones substantially bigger than the original nubs for extra strength.

I have also seen a low-tech solution using small inexpensive carriage bolts. I don't know what size they are in your country, but here in the US we would call them 1/2 inch #6 or #8 carriage bolts. They are probably just 2 or 3mm by 14mm. You'll want to measure it yourself.

First they marked the location of the nub on the outside of the priming handle shell. Using a Dremel, they removed the entire nub so that it was flush with the shell. Then they drilled a hole on the mark where the nub was. They inserted the carriage bolt from the outside and screwed a nut on the inside. Repeat on the other side. Done.

I have not performed this procedure myself, but I'm sure it's important to get the alignment of the holes correct, so the bolts align properly with the hooks on the back of the plunger. It's probably necessary to cut and/or file down the bolt to get the proper length too. And I think they dabbed some epoxy on the screw threads to make it less round, for better contact with the hooks.

I hope I explained that clearly enough. Good luck.