Sharpening diagonal pliers

Hello all,
I have some Kobalt diagonal pliers which dulled out fast cutting plastic wire ties. I am both surprised and frustrated. My Irwin ones never dull. I read a site about using a file to sharpen diagonal cutters. However, I’ve ruined more than one blade. I’m not particularly handy and I get angled wrong, etc. Any tips? I have a rotary tool set but I believe that would be a worse mistake. Thanks in advance!


Well, it is possible the metal used to make the cutters was of poor quality, so your efforts may be short lived. But, if you want to learn a set of diamond files will do the job. Having never done a pair of cutters before, the only advise I could offer is to count the strokes and take an equal number from both cutting edges to keep both edges in line with one another. Work your way up through each grit in the set.

If your cutters dulled from cutting tie wraps don’t waste your time trying to sharpening them. It sounds like the heat treat is bad or junk metal. Buy you a set of channel locks brand cutters. Great quality for the price

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You know, I never thought about that. I guess buying is best. Especially in light of my other pliers remaining sharp. Thanks!

If you’re cutting zip-ties, I would strongly encourage you to pick up some Fastcap flush cuts.

In decades of working with zip-ties, they’re the best I’ve ever found. They leave a perfect flush trim every time, no burr, and they’re durable enough to cut wires and stuff too without nicks or dulling. I use mine constantly, and recently picked up a second pair, not because there’s anything wrong with the first, but because I want to have some in the main box AND some on my belt.

The big ones are comically big; get the “micro” and they’ll fit your hand just fine.

I second that, they are really nice