corax
Explorer
Tried to hit a lot of razor edges with a file. One thing I noticed - one side of the grate has razor sharp edges from the cutting process, the other is more rounded. Put the rounded side to the inside where you're more likely to touch it. I used tape and split loom with zipties to cover as much of the edge as possible.
A twisted wire cup brush mounted on an electric angle grinder would also do wonders to abrade the sharp edge off, and probably save a bunch of time while doing a more complete job of it - just use a piece of junky plywood for backing to support the mesh while you work on it. The kind below is what I use from Harbor Freight and threads right onto the arbor on my 4.5" angle grinder