Sharpening a Weed eater ght220 hedge trimmer?

[bullhead]

I want to sharpen the blade on an old Weed Eater GHT22o stainless hedge trimmer. I got the blade off, but instead of bolts holding the upper and lower blades together, it has what looks like pressed pins on it? Does anyone know if I can punch these out or would I need to grind them off? And can I use bolts and lock nuts in place of them? I will up load a picture soon as I can.

Thanks for the help
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[blades]

Rivets, grind off replace with appropriate size nylon insert lock nut and bolt. Lot of work if its an electric unit, maybe worth while if a gas powered one.