I needed a little something to take the sharp edges off of corners. I don't trust myself with just sanding. I use Irwin Razor blades for the durability, they don't flex as much as some of the others. I used the thumb screws from my CR10s Spool holder. The razor is set up "NOT" to ride in the indent, the razor needs a bit of an angle to nick at the corner. The Corner is also a bit off of center, so you can turn the razor over and make a fresh cut. If you need any tweeking, feel free to comment. Lets be safe out there.