The material that they are made out of was changed around 6-7 years ago to a lighter weaker material , this has been posted over and over on so many threads and forums, hence why they break . The Chinese manufacturer said this to Oregon several years back. You also have to remember that these clippers were not designed for High useage for Wargames counters. Hence the breakages. Yes the spacer added helps a lot but also you should also after doing around 30-40 counters turn them on the side and tap with the heal of your hand to dislodge the “chads” from building up and causing over pressure and breakages . I think I am safe in saying all this on the ASL forums for obvious reasons .there is also
So the real design flaw isn't so much the plastic part, which is likely plenty strong enough to handle the leverage required to cut our cardboard counters endlessly, but rather that the handles do not have a proper stop. The result is that an arbitrarily high load can be applied to the plastic part when the handles are squeezed past the point required to cut the counter. The long term solution to prevent it breaking is what @von Marwitz posted - put in some sort of stop to prevent the handles traveling past the point required for cutting. That will keep the plastic part that broke from being subjected to high loads. I used a d6 for my stop:
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Sorry to hear yours broke! Hopefully with a handle stop your second copy will last a lifetime.