Your square link is incorrect. The round link is on there twice.
When mine go dull, I'm just going to order new cutters from Things Western. As much cutting as I get out of them, I know it will be worth it to replace the cutters with the exact kind made for the tool.
I also believe (though I have never had to test it) that with Things Western being a small company that I had great intial contact with, if something ever went wrong with one of their tools, they would get me taken care of well in response. If something like that were to ever happen, I would want to be using one of their cutters.
Parker