Tuesday, October 30, 2012

Banjo 5th string tunnel (dual)

In creating a banjo for a lefty, I decided to tunnel the 5th string. I realize that this would prohibit the instrument from ever being set up right-handed, save carving a new neck. Anticipating that this banjo will be around long enough to potentially be in the hands of a righty, I decided to add dual 5th string tunnels.

The unused channel does not get in the way, negatively affect tone, etc; it only increases the instruments versatility. I also left the fingerboard a constant width to the nut in order to facilitate.

Here is a view of the brass tubes used for tunneling:

The termination of the rods at the nut end looks like this:
A hole is drilled in the nut to allow the string to escape; if the instrument is ever retrofitted for a R.H. player, a new nut would simply be made with the hole drilled on the other side.

Here is a view of the brass tubing exiting the fingerboard just before the 5th fret:
As you can see, I have inserted .020 wound strings in to the hole. These prevent the tubes from crushing during bending, and as you pull them out, clear out any debris or adhesive that may have got in. This fingerboard is ebony, bound in cherry and ebony.

Sunday, June 3, 2012

Antique Stanley Pullshave

At the Picadilly Flea Market today (Eugene, OR) I scored this Stanley tool- the seller called it a pull scraper, but I believe it is probably better known as a pullshave. Veritas and Stanley both make modern versions of this tool, but I couldn't seem to find any pictures or references to this old Stanley model, presumably antique.

I know furniture builders use this type of tool to hollow out the inner curve of a chair seat, and wooden boatbuilders would also find it useful for all of the inner curves they work with. I am thinking it could come in handy for luthiery, either in carving necks where I use a spokeshave quite a bit, or in hollowing out the inside of an archtop soundboard.

The modern versions offer an improvement in the addition of a handle above the blade- this would give more control of the cut. At any rate, I think once I tune it up it should be a joy to use! The handle is very comfortable and feels massive- like it has the right mass to balance a steady pull.
I also think its cool that at least two tools in daily use- the vegetable peeler and the shaving razor- operate on the exact same principle. It somehow makes using these tools that much more comfortable.

Monday, April 30, 2012


Myrtle is a wonderful wood to work with. I used to bend it wet, but I have found that bending with no water actually works better- you get little to no cupping effect, whereas when I've used is wet it has often cupped quite a bit (not unlike maple).

Tonally, it seems to be bright and reverberant. I think it supports a crispness in the sound, and seems overall brighter than mahogany or walnut. I don't think that the bass suffers though- the high frequencies enhance the definition of the bass tones, and possibly the sustain as well.

Take this all with a grain of salt of course- I believe that most of the voice of the guitar comes from the bracing design and execution above wood choice, by a large amount. The wood just seems to accent or reinforce certain tonal aspects more than others depending on the species.


The most useful technique I have found is what I would describe as a sort of creative process of imagining the sound transformed by guitar strings/tension. If you tap every piece of wood regularly as you shape and construct the guitar, and also tap parts of completed instruments and various instruments you own, you begin to develop a sense of what the wood sounds like, and how that sound interacts with the vibration of strings under tension. As you refine this perceptive ability, you can begin to creatively imagine how each part will sound in the completed instrument by tapping as you work on it.

More specifically, by tapping I mean holding the piece of wood approx. 1/9 of the length in from the edge, lightly pinched between two fingers. This is derived from Young's modulus, or the vibration of free bars (which most pieces of wood resemble before being glued into a box shape). Each piece of wood will sound different, and some are more musical than others.

For example, dense wood such as rosewood and ebony tend to have a loud and clear pitch, like a marimba bar. Softer or less dry woods will have a muted, unclear note, and most other woods are somewhere else in between. I believe that all pieces of wood in an instrument contribute (even if an imperceptibly small amount) to the overall musical vibration/resonance, so in a handcrafted instrument it is essential to select the most musical sounding wood, or to shape the piece sin such a way as to accent that characteristic, regardless of the species.

Wednesday, March 28, 2012

Good compilation of tonewood sources


Thanks Cone Guitars for this thorough list.

Oregon locals should add:

Urban Lumber
2440 Main Street
Springfield, OR 97477

(541) 988-9663

Tuesday, March 27, 2012

Apple wood as tone wood for bouzouki

Lately I've been experimenting with apple wood as tonewood. It compares in density with cherry, a bit softer than maple, beautiful color, and is stiff and musical when tapped.

Apple tonewood is all but impossible to come by. About 6 years ago I had a huge (almost 4' diameter) apple felled in my back yard. I had it milled and dehumidifier kilned, and then it air dried for about 5 years. Just now, it is coming into it's own sound-wise- I resawed a piece of it and the nice tap tone made me want to try building with it.

Here is an Irish bouzouki I recently built with the apple from my yard.:

The sides bent easily and the wood has a smooth surface feel that takes finish beautifully. I am also encouraged by the tone- I would say it is more in the warm type of tonewoods like mahogany or walnut, but it also seems to have clarity and sustain in the high register. It's actually right in the pocket of what I seem to go for- granted design, bracing and top wood play a much more substantial role in the equation, but the apple seems well suited for stringed instruments.