Can I Use Sandpaper on a Triangular Rod to Sharpen Saws Instead of a File?

Theoretically, it could work if everything is set up just right, but practically, it's a hassle. The sandpaper would shift and lose its abrasive very quickly, and making the triangle shape might be tougher than just using a traditional file. You're better off just getting a proper file.

Honestly, saw files aren't that expensive. Why complicate things? Just grab a file and make your life easier!

Using sandpaper won't really do the trick. A saw file has cutting edges along all its sides, which a sandpaper-wrapped rod just can't replicate. When you fold the sandpaper around a corner, it won’t hold the abrasive well, and you're likely to ruin your saw teeth quickly. Sure, it’s low cost to try, but I wouldn’t expect great results!