can you sharpen forks?

Like if they've been mangled in a garbage disposal? I assume you're not talking about fine silver or silver plated, but regular stainless steel flatware. Just use a fine metal file or emery cloth, available at most home centers or hardware stores. You can also get grinding inserts to use in an electric drill but that's unnecessary unless you have a lot of them to do. If that were the case, I'd buy a small bench grinder with a fine wheel, but for just a few, I'd use a metal file.

We had some trouble with silverware getting chewed up in the disposal when our son was little, but we seem to be past that now. I started keeping a small metal file in the junk drawer to clean up the edges to make them smooth again.

yes

prisoners do all the time, and stab people with them.