Ok,you have a coupe of options as I see it. It would be possible to drill two holes about a half inch above the handle(blade side),cut, shape and drill the guard to match,(clamping and drilling together would be best), and then pin and peen, or bolt if you have to. Or you could get it welded. I am describing a guard that would be on one side of the blade only.
Or you can get a knife that is designed for the purpose you've intimated. These are made by Cold Steel, and are around a hundred bucks.
GUN CONTROL, I GOT THAT
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