Stay in Tune Vol#5
By Luthier Patrick Podpadec
Hello to all of you “Voice” readers. I can’t believe how fast the time goes in between the articles . I’m always trying to think of something new to write about and just about the time that I do it is time to start writing again. Before I do, I would like to talk a little more about frets and some of there inherent problems. In the last article, ( I hope you got to read it) I started to talk a little bit about fret leveling. I thought I might try to expand on that subject in this article.
The first thing you do, is remove the strings. By doing this you will notice that by looking down the neck from the headstock to the body you should notice that the neck has a slight back bow in it. This means that the area of the neck between the 5th and the 9th fret is higher than the first fret and the12th or 14th fret. You can check this more accurately by placing a straight edge on the frets. There should be some “rocking” going on there. This means that you have to relieve the tension on the truss rod by turning it counter clockwise. You must make sure that you use the proper size Allen key or the proper size nut driver or socket . If you strip the fine thread on the truss rod you are pretty much screwed . This is a whole other intensive repair that you do not want to get into. The truss rod is a integral part of any setup work that is done on all stringed instruments ( those that have one) When it is not functioning properly you wont be able to set up the instrument correctly.
So, now that you have successfully loosened the truss rod you can lay your straight edge back on the frets and check it to be as flat as possible. You can try to slip feeler gauges in between the frets and the straight edge. Do this on as many frets as needed until you have, either no gaps or very few measuring just a few thousands. Remember that the goal here is to try to get the fingerboard as flat as possible before you start filing any fret material away. If you were to start filing away on a bowed surface you will be removing far too much of the high frets before your file reaches the low ones.
Make sense so far? I hope so. Now, before you start filing with your 10 “ flat bastard file, and I do mean flat! .Check it with straight edge ruler or something else that you know to be perfectly flat. I have come across many files, even brand new ones that have a slight bow to them. DO NOT USE THEM! It will only complicate your job or drive you crazy later trying to find out why your neck is still buzzing after all the work you just put into it. You take a permanent black magic marker and blacken out the tops of every fret This is done so that you can tell where you have removed material from the fret and where you haven’t. You might have to repeat this procedure several times due to the severity of your frets. It doesn’t take a lot of force to remove the soft nickel/silver material from the frets. Usually the weight of the file itself is about all the pressure you need . You also have to be very careful of putting to much pressure on the fingerboard while your filing because if you are pushing down too hard you can easily Bend the neck out of its “straight” position. I use small sand bags that I have made up to place under the neck to stabilize it.
Now if you have gotten this far your half way done. ( no one said it was gonna be easy!) This is where most people get hung up because the next procedure requires a specialty tool called a “crowning” file. It can be purchased from luthier supply houses such as “Stewart MacDonald”or “ Luthier Mercantile”. There are many styles ranging in price from $40. to $120 There are two sizes that are used for the different size fret wire that is on guitars, basses, mandolins and banjos. They take a certain amount of practice and patience in order to use them properly , but if you where to skip this procedure you are only doing half the job. I have seen and fixed many half done fret jobs.
It is possible to use a modified triangle needle file. You can grind down the two lower sides of the triangle so that the corners don’t dig into the wood of the fretboard. Be very careful when you file off the flat edge of the fret that you created in step one of the filing. You need to work both sides of the fret and be sure to try to “round off” the fret evenly.
From Patrick at Wood-n-Strings