August 9, 2016
We do a lot of set ups on acoustic guitars, and a common task that we do as part of a set up is reducing the saddle height to lower the action of the guitar. The saddle might need lowering for a number of reasons: perhaps the soundboard has expanded slightly due to an increase in humidity in the ambient conditions the guitar has been stored in, or perhaps it was simply left too high at the factory to begin with. In addition to that however, as guitars age the components can start to move in relation to each other causing the neck pitch (ie the angle the neck sits in relation to the body) to be shallower than it originally was. Eventually this becomes so significant that there is no longer any room to lower the saddle further, so more drastic measures are necessary to lower the action.
In the old days, the obvious solution was to get out the plane and start shaving: either the bridge was thinned in height or the fingerboard was planed at the nut end to add an extra degree or two of angle. The problem with this is shaving the bridge can impact the tone and structural integrity of the guitar and shaving will also change the feel of the neck as well as the other two issues, so neither solution is very good. As the vintage market began to gather pace in the 1970s and the value of older Martin and Gibson acoustics started to creep up, more sophisticated repair techniques were developed and gradually the process of resetting the neck became established as the preferred approach. In this process the neck is removed from it’s mortice in the neck block and the angle can then be adjusted and the neck refitted at an appropriate angle. Unlike shaving and other solutions, it’s a process of restoring a guitar to its original state rather than modifying it to compensate for a problem, and it’s the only one we’re happy with on a high quality guitar.
In this blog we’re going to look at a neck reset on a 1976 Fylde Goodfellow. Later Fyldes are designed with a bolt on system but the early ones have a traditional dovetail joint as you might find on a vintage US guitar, so it’s a good example of the process.
Step one: First we need to release the fingerboard extension from the soundboard. We're going to do that by applying heat to the fingerboard then as the glue softens we'll use palette knives to gently prise open the joint.
Our method of applying heat may look pretty basic but it does the job very effectively. The iron is heating a metal bar which radiates heat over the fingerboard extension. It's a relatively slow process but much better than applying the iron directly and heating too much too quickly. We can check how warm things are getting by feeling the underside of the soundboard through the soundhole.
Once the glue is softened we use a couple of palette knives to gently separate the fingerboard from the top of the guitar. If the palette knife doesn't go in easily then the glue isn't soft enough yet.
Now that the fingerboard is detached we need to get at the glue that holds in the neck itself. To do this we need to drill a hole somewhere that won't be visible once the guitar is reassembled and the best location for that is to use one of the fret slots, so one of those frets is going to come out.
With the fret removed we can drill down into the neck pocket - we're aiming to get into the void between the back of the dovetail and the neck block itself so that the steam will have lots of access to the sides of the dovetail where we need to soften the glue. On a Martin guitar we would expect to find the pocket directly below the fifteenth fret, but the Fylde has a smaller dovetail so we're angling our bit forward.
We're almost ready to start working on the joint now - these clamps are going to allow us to put a little controlled pressure on the joint.
Now for the steam. The rubber tube you can see in the picture has a needle on the end that goes into the neck pocket via the hole we drilled through the 15th fret. Depending on how the block is constructed there is the potential for steam to go everywhere which is not exactly great for a delicately built acoustic, so we do this stage with one person working on the neck and the other armed with a lot of paper towels blocking off escaping steam and absorbing moisture. We're looking to keep a close eye on both steam and temperature around the neck area whilst we work on loosening the joint. Since I'm on towel duty for this reset, time to put the camera down and concentrate!
With the steam going in the right direction, it's only a matter of time before things start to move. Pretty soon we hear the telltale click of the joint seperating under the gentle pressure of the cam clamps, then a quick tighten of the cranks and the neck join slides smoothly apart.
Let's see what we're left with: the neck has come out cleanly and there's lots of old glue to take care of. We'll start carefully cleaning up all of this residue next, then we'll be ready to have a look at the new neck angle.
Here we can see the joint in the body. Again, there's lots of clean up to do to get rid of all that old glue before we work on the joint. If you look closely at the unvarnished part of the top that was previously under the fingerboard and around the mahogany block, you can see it's quite damp and swollen looking, so it's important we wait for any moisture from the steaming process to dry out before we work on it - if we fit it now the joint could change as it dries out. Unfortunately, that means a break in the blog as well, but we'll be back!