Originally posted by BillyB_from_LZ
From the desk of luthier Karl Hoyt...
Dressing Fret Ends;
With the drastic changes in humidity which accompany life in many regions of the country, there are times when the fingerboard will dry out and shrink, causing the ends of the frets to protrude. The remedy is pretty simple. All you need are very basic hand tools and a bit of patience.
1. I have done quickie fret dressings with the strings left on: but it is better to at least loosen them and move them out of the way.
2. You will need a smooth, flat file and a small triangular or needle file. You will also need some masking tape.
3. Hold the file so that it is parallel with the fingerboard edge: slowly and carefully file the fret ends following the fingerboard with the file until theyre no longer protruding. You are done with this step if it feels as though you are riding on the wood rather than cutting metal. Dont be concerned about the file taking finish away. Since you are using a file with very fine teeth, you wont be affecting the finish too much. NOTE! Do not file the fret ends in an up and down fashion, this can potentially cause a fret to become loose.
4. Next, tilt the file to mimic the bevel of the fret ends: and again file parallel to the fingerboard until it feels like you are riding on wood.
5. The frets should be trimmed pretty well now. But you must check to see if the filing caused the fret ends to be sharp. If this is the case: follow these steps.
6. Tape off the fingerboard right up close to the frets. You will be carefully filing the fret ends to remove any sharp burrs but this is a place where you can dig into the fingerboard if not careful. The tape will help prevent this.
7. Holding the fine triangular file perpendicular to the fingerboard and at about a 20 degree angle to the fret end, lightly file each side of the fret to remove any sharpness. Check it frequently with the pad of your finger to ensure that the fret end is no longer sharp.
8. Once the fret ends are trimmed, you may remove the tape and buff the fret ends with a small piece of 400 grit wet/dry sandpaper (used dry) to remove any mill marks. Its not necessary but you may polish the fret end with 600 grit paper once you have done the 400.
9. you can touch up the finish (you probably wont need to ) by taking a dab of thinned polyurethane on a rag and briskly rubbing into the affected area. This is only usually necessary if you tried to hurry the job or didnt tape off the fingerboard prior to trimming the fret ends. Tiny scratches can be hidden by applying another coat of Minwax finishing paste wax to the fingerboard.
NOTE: you can use 220 grit sandpaper wrapped around a flat block of wood to trim the fret ends if you dont own a small file. Likewise, a fingernail emery board will work to clean up the fret ends. However, the cost of tools to do this project is only around ten dollars. The sandpaper may mar the neck finish easier than a file will, so be advised of this.