Hi -
From what I am understanding of your cutter, there are two purposes of the bolts. The first is to clamp the blades in place, and the second is to shear when force exceeds a certain threshold. I wonder about two things; 1) Are you keeping the blades shaped approximately the same shape (cutting edge, etc.) as the factory put on them; and 2) since clamping force of the bolts will change substantially (up to 25%) depending on whether the bolts are lubricated before they are torqued, are you lubing the threads?
I also wonder about having some large washers under the blade side of the bolt, in order to spread out the clamping force and increase the amount of friction on the blade since more of the blade would directly clamp to the blade adapters.
Lastly, if the blade adapters are now worn from the use / bolts shearing /etc., then they can be not providing the functionality in the blade retention that they should.
Just some thoughts, as usual, they are worth *every* penny that you paid for them ...
:>)