I was just reading about nut files. There's a ton of different things they're using....a guy took pictures of the slots after the different types were used. Started thinking about what would work best without spending 50.00 for a a few files.
I was going to fix a binding "G" string with a file then it dawned on me. Use an old piece of guitar string. Cut it long enough to put loops on both ends. Cut a little piece of 600 or 800 grit sand paper. Crease the paper around the string. Dribble some super glue along the crease. when it starts getting tacky then press it around the string. It forms the radius of the string.
It took me 15 seconds to fix the binding slot. And it's nice and smooth. It actually cuts smoother then the file. All you need is some dfferent size strings, sandpaper (600 grit or finer), and some super glue. I've used sandpaper by itself but it's nothing like this.....you get the radius of the string. Here's a picture.
I'II have to try that.
I use oxy/acetylene tip cleaning files. The one's the welders have in the overall pockets. No overly expensive and a size to suit your needs.
There's a guy online with a 20x picture of a nut cut with the cleaning tips. The cut was very clean. I've never used them....just used a file. You can use different sandpaper grits. It did make the slot very smooth. Works like Abrasive chord except I have the exact string size. Abrasive chord is about 12.00 with shipping unless you can find it in stock somewhere nearby. I haven't been able to.
I'm so glad I own a set of nut files.