Volume 49 - Truss Rod Adjustments

Written by Patrick Podpadec on . Posted in Northcoast Voice

             

               

                               Stay in Tune                                          vol#49
                                                                         By: Luthier Patrick Podpadec

Summer is in full swing now and everybody is playing music. Everyone I talk to lately is telling me about this concert or that concert or “I'm playing there next week” or “Are you coming to my gig tomorrow?”. It just seems that “music is in the air”. I know it sounds like cliché', but it's true.
This is the time of the year that I get two and three calls a day for some minor repairs. Many of them have to do with truss rod adjustments. You might have found that your guitar's neck has suddenly seemed to have warped or bowed a little more than normal lately. This is not uncommon for this time of year. With the excessive humidity in the air the guitars tend to absorb more than it's fair share of water into the wood. This will result in some minor swelling of the top which sometimes puts more pulling pressure on the neck and can tend to “bow” it more than usual. You might find that when you pull your guitar out of it's case that the strings are tuned a little sharp. You would think that most of the time that strings under tension would loosen up or stretch which would make them go flat.. I'm not completely sure about why they go sharp, but my guess is that the humidity swells the wood enough to actually pull the strings tighter. If this happens to your guitar ,it's by no means the end of the world. It's very common and can easily be remedied by a a truss rod adjustment. There is a long threaded rod that runs the length of the neck under the fingerboard that is there for this very reason. I believe it was the Gibson factory that started installing them in their guitars in the 20's and early 30's when more and more players were turning to steel strings so they could get more volume from their instruments. The steel strings obviously put more tension on the necks and Gibson designed the truss rod so that they would have a way to adjust the neck back to it's normal playing condition after the neck would start to pull up or bow do to all of the added tension. It is a very ingenious idea and has served the guitar industry well for many years. There is a truss rod in virtually every guitar made today. Except for classical and flamingo guitars(which don't have the added tension from their nylon strings) Even the very inexpensive instruments come with truss rods installed in them.
There are a few different styles of truss rods that could be installed in your guitar. There is a single rod with a nut on one end and a fixed end . (this means that the opposite end is some how “fixed” or stabilized from moving when the nut is turned on the other end. By turning the nut on the threaded end clockwise and the other end not being able to move, the rod will naturally start to bow which will bring the neck back to being straight again. There is also double rods and rods that can be adjusted from either end (which are rare) and rods that can be adjusted to take a bow out (clockwise) or put one in by turning it counter clockwise. Although this feature is rarely used it can come in handy at times. I install the double action truss rods in all of my guitars. Not that I have ever had a neck of my guitars develop what would be known as a “upbow”, but I feel that it would be a lot easier to repair the problem (if it were to ever occur) with a truss rod of this type rather than having to refret or possibly replace the warped neck.
Some caution should be taken when adjusting the truss rod. Most articles that are written about neck adjustments refer the readers to seek out a professional luthier. It is very easy to get yourself into trouble or to “over do it”. The last thing you want to do is to break the truss rod. I like to take the tension off of the neck (by loosening the strings and then back the rod off (counter clockwise) until there is no tension at all . You can feel this because the nut will be loose on the threaded rod. I then start turning the nut clockwise until I feel that there is some tension on the rod. I only turn the nut about an 1/8 of a turn and then check my progress of the neck. If you lay a straight edge on top of the frets you can see the neck starting to “flatten out” You should constantly be checking the neck with each small turn of the nut. You will also start to notice that the tighter you go the harder it will be to turn the nut. This is where it can get tricky. Usually most factory setups allow a small amount of “relief” in the neck This is a small amount of space or curvature if you will that is left in the fingerboard (anywhere from .005 to .015 thousands) between the 5th and 9th or 10th fret. This relief is for the movement of the string as it is being plucked. I would then tune the guitar up to to A440 and then recheck the neck. More than likely the bow has gotten larger than it was with out tension on it. Laying a straight edge on the frets you can continue (very carefully!)turning the nut and checking the straightness of the fingerboard. If you have never attempted this procedure it may be advantageous for you to ask a professional to give you a hand. Some may help or teach you and some may not. I personally do not have a problem with people trying to do some of there own minor repairs. It gives me more time to concentrate on the harder procedures that most people can't and won't try for themselves. So if you are feeling “Lucky” you can try to do it yourself and if your not you can call me at 440 474 -2141 Have a good summer and maybe we will see you at the next musical event!

Thanks Again!
Patrick from Wood-n-Strings/ Liam Guitars