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body shape

As you can see from my previous posts, the CNC machine was used for much more than originally intended. So as a next step it came naturally to also apply it to fine-tuning the body shape.

As CamBam isn’t really the best tool to draw Bezier curves, I resorted to good old Adobe Illustrator to draw the outline:

Although not trivial, this could then be exported as DXF and then imported into CamBam to base the toolpath on.

I had to order an extra long end mill tool to cut all the way down from 40mm height to ground (took a while too…)

This slope actually done manually:

The next design decision was not what I had planned (although one guitar maker had warned me when I bought the ziricote). The problem was that this slab of wood was darn heavy:

More than 50% above a standard Strat body:

So as I needed a lot of room for electronics anyway, I decided to cut pockets everywhere, turning this axe into a semi-acoustic (or maybe quarter-)

Much better now :)

headstock

As you might have guessed from the previous posts and pictures, the amount of wood I left for the headstock would not allow for the traditional placements of the tuners. In other words, it’s a so-called head-less design (technically there’s actually still a head – it’s just much shorter)

So this approach calls for two components:
First, you need tuning machines down at the bridge. This is relatively easy to source – in this case I went for ABM bridges with Graphtec pickups. Thanks to Peter Borowski from ABM, Berlin for helping with this.

The second part are the clamps to hold down the strings at the headstock. While there are purchase options for these too, most do not come as single pieces but as a block for all 6 strings. Which, again, doesn’t work with the wide string spacing I prefer.

So I decided to come up with my own design, where the plan was to work as much as possible with the wood itself, rather than attaching a full-metal solution.

Of course metal is needed in some parts, otherwise the wood would wear down over the years. So I designed an inlay where the string runs over a tiny metal bridge, with slots at each side for the metal clamp.

I milled this inlay out of a piece of brass that I had still lying around. This was the first time I used the CNC for cutting metal, so I was a bit nervous if it could do the job, but things turned out nicely without breaking anything:

And the pocket to match:

This was then extended with deeper holes for the clamps:

And holes from the back for screws to hold them down:

Tada, first string clamped down:

neck joint

I decided to practice the neck joint with a piece of maple I had left over, because I was afraid to get it wrong and then not being able to undo the damage.

I went for a slotted design to stabilise the alignment. Used three M6 Rampa wood screw inserts.

This seemed to work fine, so I applied it to the Ziricote body…

…as well as the neck:

And here’s neck and body joined for the first time:

neck

Here’s the neck with the truss-rod already in place. You can also see the fretboard behind it – I didn’t cut the slits for the frets myself, although with the CNC machine that would be possible of course. But back then when I ordered it, that wasn’t the plan

Mating fretboard and neck:

Not the most professional clamping job, but it worked out fine.

Milling the sides for the correct width:

The completed rough cut of the neck:

The headstock is still rather blocky, as I wasn’t sure what shape it should have, so I left more material on in order to have options.

Also note the round shape at the end where it meets the body. It follows the curve of the sound hole of a classical guitar. More on the neck-body joint in the next post

CNC

I bought this initially to
a) do quick PCB prototypes,
b) cut irregular holes into enclosures, and
c) for some very specific guitar jobs.

As it turned out I’ve used it progressively more for c), a little for b), and not at all yet for a).

The main guitar job I had in mind back then was to precisely plane the body and neck areas where they will be joined, as that’s something hard to get right with just manual tools.
But after playing more and more with this machine, I found myself applying it to many other tasks, while also improving my CAD/CAM skills.

The first step was to test the machine with the manual controls, so I made some exploratory cuts in regions that would be cut away anyway:

Next, I wrote a number of scripts in gcmc, i.e. one step above bare-bones g-code. This is used to cut a narrow trapezoid from the bridge to the end of the body to delineate the area where the strings would go.

Then, after this turned out nicely, I wanted to try more advanced stuff. So I bought a simple CAM application (CamBam) that would allow me to design basic 2D shapes that would then be milled to a certain depth (what is commonly called a 2.5D approach).

I applied this first to pockets for the bridge elements to ensure that they are perfectly aligned.

The software can calculate a tool path and then export this to g-code, which can be read by the CNC controller, in this case Mach3.

Here’s the machine in action:

And here the result:

wood sourcing

A lot can be said (and fabulated) about the tonal qualities of the various types of wood used in guitar making, alas, having not much personal experience in this field, I admittedly based my choice largely on visual qualities.

In particular I came across this neck piece of Ziricote, a tree I had never heard of before, but immediately liked due to its intricate markings:

As I prefer single-type wood guitars (save for the fretboard) I then faced the much harder task of finding a large enough Ziricote piece for the body. Most dealers said this was not possible, but after much back and forth Nebelheim Tonewood procured a plank that seemed promising (thanks much to Manuel Wemmer for helping with this):

Note how the dark core is surrounded by lighter wood.

Of course this wasn’t wide enough for a one-piece body, and even a two-piece didn’t pan out because I had to work around a crack. So I ended up with this cutting plan:

Put together like this (Photoshop simulation):

With an overlay of an early design sketch:

I then took this to a local shop in Berlin to do the actual cut and paste. Thanks much to Guitardoc and Anthony Schneider in particular for the help!

I forgot to take a picture of the raw assembled block, so here’s one at a later stage where the upper curve has already been cut out:

More on the machine in the background in the next post

new guitar!

So I decided to build myself a new guitar.

Why?
I guess it can be summed up as an attempt to create a hybrid between my two current instruments and the playing styles associated with them, but also to use the opportunity to integrate as much guitar electronics as possible.

So for reference, here’s my solid-body nylon string that I build in the early 90s:

I built this because I wanted to play electric guitar in a band, but also apply my classical guitar education, i.e. finger nails on nylon strings. The latter don’t work with magnetic pickups of course, so piezo transducers had to be used. I first tried to mount them on a normal e-guitar, but didn’t like the tight string spacing. I also prefer the flat fretboard of classical guitars.

Back then, no one built guitars with this design approach and only later did I discover a small guitar company that had been doing this for a while: Paradis.
So without any previous woodworking skills but being the stubborn, determined guy that I am, I embarked on a mission that took me around two years to complete.

I don’t expect the new guitar to be done any faster.

Anyway, here’s my other axe, a 5-string Marathon bass:
(free beer for anyone who recognizes the logo on the sticker)

Like the nylon solid-body it is equipped with piezo pickups. Not that these were strictly necessary, but over the years I’ve come to love their particular sound.

One side-effect of using these piezos was that I “had to” make use of the fact that they provide a signal per string. In particular applying distortion to each channel separately before summing them (I still remember going to the local guitar store and plugging into 6 Fender amps :). These days polyphonic effect processing is of course at the core of my practice, both in my Ganzfeld and IMD duos.

So the new guitar will have these pickups as well.
But what will be new? What do I mean by hybrid?

Well, for one thing it will be a baritone guitar, i.e. between the standard E-tuning of a guitar and the bass an octave lower. I’m aiming for B-flat, not the least because both my duos are with trumpet players.

This tuning will also allow me to use wound strings across the board, as the highest frequency of 233.1 Hz should work fine with an 18 gauge string.
The reason I prefer wound strings these days is that they respond much better to the various experimental playing styles I typically use in my practice, wether it’s scratching the finger nails along the strings or applying various objects like bottle-necks or metal sponges.

However, from the nylon solid-body it will adopt the flat fretboard as well as the wide string spacing.

And with regards to the guitar electronics mentioned above I plan to include:
– preamps tailored for the high-impedance piezos
– analog-to-digital conversion
– fret-scanning
– sustainer
– on-board sound processing
– sensors for sound control
– acoustic transducers

Data violin

For Jon Rose in collaboration with Martin Riches.

This is a MIDI-controlled music robot. While labelled as a violin it is actually a hybrid instrument, with its viola body, but guitar-like frets, and a circular bow as in a hurdy-gurdy.

Martin Riches has been building similar instruments for a long time, but we decided to team up on this one in order to improve upon the control electronics and software design. All solenoids and motors have now continuous control where separate envelopes can be assigned to all elements at a high temporal resolution, allowing for refined articulation.

data_violin_1

Strophonion

The Strophonion is a sensor controller devised by Alex Nowitz for manipulating his voice in live-electronic contexts. It was initially developed at STEIM, using their expertise in hardware design as well as their software offerings, in particular LiSa and Junxion.

I got involved starting in 2014, when I helped building the next revision of this controller:

stroph

The electronics are largely the same as in the previous version, however we added an option to connect the controllers thru a cable in case the wireless system breaks down. The basestation though is a completeley new design.

Most notable are the 3D-printed shells which were designed and built by chihauccisoilconte. Here’s the new and old designs side by side:

stroph-compare

In the following years, Alex and I embarked on a long journey to also update the other half of the instrument design, i.e. the software. The aim was to implement the signal processing in a more open, flexible, and expandable environment, so the complete functionality was transfered to MaxMSP. This process take longer than expected, but in late 2018 Alex was able to present the new version of the Strophonion in a concert as part of his PhD project.