Scratching the top wasn't an issue. But you make a good point about sawdust lighting up with the metal sparks. I vacuumed all the inside out before doing so though and there were no issues. I take all safety precautions before anything I do. It's expedient and accurately cuts just as though I was cutting wood but slower. Still... it seemed a little scary because I haven't tried doing this before. I'm rethinking it and wanted to see if anyone else has done this.