These cheap wire crimpers often have the problem that the rivet joint is loose making it hard to crimp connectors. I first tried hammering the rivet to tighten it up, but that didn't work well enough. This simple hack fixes the problem.
There's now little side to side movement in the crimpers.
M6 x 20mm bolt
M6 Nylon locknut
M6 large washers x 2
Spanners for the M6 bolt
Grind away the head of the rivet so that it can be removed.
Hammer the rivet out using a punch/
The two halves should be separate now.
Re-assemble the crimpers using the M6 bolt and washers in place of the rivet.
Tighten the locknut so that there isn't much give in the joint and two halves can still move,