I don't want to be a downer on those using the slot style but I tried one a week or two back, and it ruined the blade. Luckily it was a backup swiss army but I think I'm done with quick and easy. I'll try my hand at sharpening by hand. A few days later I bought a DMT dia-fold, for both regular blade and serated, online. The serated seemed to work well on my leatherman.. I'm still waiting for the reg blade style.
I might buy the speedy sharp for an old machete. Its dull as all heck, and it was only $10.... Always good to have a backup machete when the zombies rise.. yes, kidding
some multitool knife blades are chisel ground and can't be sharpened this way. I really do not like chisel ground blades.
the other thing is that if the blade was not sharpened at the same angle as the sharpener, it won't work either.
I have never been a fan of carbide sharpeners, but I have a smiths sharpener and it works pretty well. it has carbide, ceramice, and a rat tail type file.
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Warning - I am not an expert on anything having to do with this forum, but that won't stop me from saying what I think.
Bob