Stay in Tune vol # 42
By luthier Patrick Podpadec
There is a part of me that loves the winter .When I put on the coffee in the morning and go out to my warm shop and start working on some cool project it gives me a real good feeling. Then there is the 100ft. path I have to shovel to get there and the ice I have to chip away at the door step and did I mention the 15 degree below wind chill factor? Oh Well, it all as a way of working itself out I guess.
I had an interesting repair over the holidays that required me to reset the neck on a “lute” type instrument. I say that because the body shape (being tear dropped shaped and having a dome staved back) and the neck were similar at the body joint. It originally had a “pin” bridge in the body, but over time this had produced a lot of tension over the large thin top of the instrument and had caused three or four large cracks in the top. The short neck, that doesn’t have any heel support at the body had pulled forward to create a huge, unplayable action. The previous repair man must have decided that it would be a good idea to just shave down the bridge and saddle as far as it can go and attach the string to the end of the body (Like as a tail piece does). This takes a lot of tension off the top so it won’t continue to crack, but at the same time doesn’t fix the first problem which is having the proper neck angle to the body. Neck angle is probably the most important aspect to any stringed instrument .Without proper neck angle, everything that you do to try to adjust the terrible action will result in you just chasing your tail around the guitar or whatever instrument you have. If you lower the bridge, which is the first thing most people think that you have to do, you will be compromising some other aspect of the playability of the instrument. It may cause a difference in string tension which effects sound projection or the break angle behind the saddle which can cause your strings to buzz, or a host of other playability issues may arise from a bad neck angle. It happens to many guitars, mandolins violins and lutes too. On the lute I had to approach the neck set differently than I would on an acoustic guitar. Instead of steaming off the neck, I had to cut through the fingerboard to the neck at about two or three frets up from the body joint and remove the fingerboard to expose the neck joint. I also had to remove a section of the top (under the fingerboard) so that I could get to the neck joint. What I found was that the neck joint was very badly fitted which caused the lifting problem in the first place. I decided to rout out the whole male end of the tennon joint which led me to have to rebuild a new tennon for the neck. Are you still with me? If so, then I had to refit the new tennon into the new routed slot and set the angle so that the “plane” of the finger board would line up with the new height of the bridge that I rebuilt (another story for another article) so that the break angle for the strings behind the bridge was adequate enough to put good down pressure on the top to be able to drive the sound. It was hard to do, but very exhilarating when all of it got put back together and held without incident The constant string tension on the neck/body joint is prone to this problem. It’s only in the case of the instrument having a combination of all the factors such as perfectly dried wood, wood that the grain orientation is extremely stable and not to mention the exquisite joinery and craftsmanship, that make up the “perfect guitar that doesn’t need a neck set after 20 or 30 yrs. If you own one of these instruments I highly recommend that you keep them or at least in your family. It’s difficult to put a number on it , but I would say that 30% of the guitars I see come through my shop suffer from needing a neck set. The problem with neck sets are they are not very easy to do properly. The first step, taking the neck off can cause a whole host of problems in itself. You must be well prepared for anything that you might encounter. I have had the neck block come loose from the sides and back. If this happens, you have to know how to fix that problem correctly before you can continue on the neck set problem. Many times necks splinter or chip off large chunks of wood on the dovetail or on the soft spruce top. You must always address these issues first. Once you have the neck successfully off of the guitar the real fun begins. Trying to evaluate the exact neck angle and making sure that the center lines of the neck and body co inside with each other and to make sure you don’t “overset” the neck. I’m sure I have said this before, but every time I have to do a neck set a certain amount of anxiety builds up that keeps me very focused on what I’m doing so as not to make any mistakes. There usually always involves some sort of finish touchups around the neck joint, only because its’ literally impossible to not chip the old brittle lacquers on the older instruments. Here again there is some skill involved in that aspect too. Although this is a very tricky and difficult repair at best, it is probably the most important because without it is very hard to “setup” an instrument to it’s proper playability without the neck angle being correct. Next week I’ll explain about raising the bridge on the lute. Have a “warm” week!
Patrick from Wood-n-Strings.