Stay in Tune vol#32
By Luhtier Patrick Podpadec
Were back again! Having a week off is nice . My family and I did a little camping during the past week. We always plan on going camping 3 or 4 times every year , but the summer goes by so fast that we usually only get to go about twice before the kids have to go back to school. I guess we will just have to go sometime again in September.
In the last issue, I had talked a bit about resetting a neck on acoustic guitars. Although it is difficult to vision the process without pictures , I will attempt to explain the procedure as best I can without being to confusing. To start out with it important to know when or how to determine if your instrument is in need of a neck reset. After you have lowered your action by lowering the saddle as low as it can go, you must sight down the neck, looking from the headstock down to the bridge. You try to see if the top “plane” of the fingerboard planes out to the top of the bridge. You can also take a straight edge and lay it on the fingerboard and slide it down the frets until it touches the bridge. If it planes out lower ,even as much as 1/8 of an inch, and your saddle is as low as it can go, You will be needing a neck set. I have seen many times where someone has tried to lower the bridge by taking it off and lowering it from the bottom and regluing it back on with hopes that this will solve the problem , but it doesn’t. It only weakens the bridge and doesn’t really change the angle enough to give you any saddle height. It is good to have a general knowledge of the types of joints that are used to attach to neck to the body of guitars. The most common in the past has been the “dovetail joint”. It’s been used on acoustic steel string guitars for almost two centuries now. Another type is called a “Spanish Heel” and is used primarily on classical or nylon stringed instruments. The method of neck removal that I’m explaining in this article will not work for the Spanish heel type body joint. Please do not attempt to repair a neck angle problem on a classical guitar. It is not done in the way that I’m telling you here. There are also bolt on necks , used by Taylor , Martin , Santa Cruz, and many others. There is also the “pinned rabbit dado” used by Gurian and others. I have seen instruments attached with 3or 4 dowel rods. It is important to know the type of joint that you are dealing with before you attempt take it apart. The method I’m explaining here is only for the traditional dovetail joint.
I first start out by removing the 15th fret on the guitar. Or the first one after where the neck meets the body ( some guitars have the neck/body joint at the 12th fret). I then taka small 1/16th inch drill bit and approximately 1/3rd of the way into the width of the fingerboard I drill a test hole, angling it slight towards the head stock. I drill down deep enough ( through the fingerboard , and the spruce top) and hopefully find an open gap area . You will be able to feel that your drill bit is not drilling into anything. This tells me that I‘ve found the small area of the bottom of the dovetail joint. This is good. And you are lucky if you find it with just one attempt. When you use a small enough bit and drill in the center of the fret slot the hole will be covered by the fret when you put it back together. You may need to fill the hole with some matching fingerboard wood and recut the slot so that the fret “seats” well in the slot. Now that you have located your joint gap you must heat the tongue of the fingerboard ( this is the portion of the board that extends over the body of the guitar) to release the glue so that you can remove the neck from the body. I usually use a household iron for this. I also use some 3”x5” roofing tins and place them on either side of the fingerboard and over the sound hole to dissipate the heat away from the top of the guitar. It is very easy to blister or damage the finish by accidentally touching it with the hot iron. Be very, very carefull! You don’t want to have to refinish the top along with this neck set. There is also commercially available heating blankets that you can lay on top of the fingerboard to heat it up ,but they can be expensive. After 3 or 4 minutes of heat you can try to work a small thin flat spatula type blade into one of the corners of the end of the fingerboard. With a few attempts and reapplying some more heat you will find that you can work the blade under the board and loosen it from the top. Again you must be extremely careful because it is easy to dig too deep and get into the fine grain of the top and rip into it very badly. Start slowly and don’t be afraid to add more heat if the glue is being stubborn.. Well if you have gotten this far without screwing any thing up, I will explain the rest in the following articles. Please remember if you attempting this for the first time or even the first ten times, please use a guitar your not afraid to ruin or are not getting paid to fix. Till next time.
Patrick from Wood-n-Strings