Q: Our contractor had one of his workers sand our hardwood floors across the grain. Now no matter what they do it shows lines or grooves across the floor.
A: I have on occasion sanded on an angle, about 30 degrees to flatten a floor. I’ve never had any issue then going with the grain and removing the scratches. Perhaps they are using too fine a grit. Go with 40 or 50 grit and don’t run with the machine.