News And Updates

So, will it be ergonomic? I hope so, and I think so. To sanity check the design slightly, I made a 1:1 scale cardboard mock-up to mess around with.

Out of the four different playing positions, the last one may not be feasible, but the other three felt very, very good. Next, having verified that it will be a working design, I’ll start making the routing template for the body.

Ergonomic guitar design only solves half (OK, maybe a little bit more) of the problem. What about the picking hand? Little Guitar Works have looked at the picking hand for basses, and have a patented solution that includes it.

I wish I knew who did another piece:

I was very happy to find one in an old guitar case that I hadn’t opened for a looong time. I had another pick as well, made from some kind of animal horn. The one in the picture is made from some kind of bone. They are amazing if you ask me! I did like the horn one better and it was pretty worn, but I can’t find it.

Not only do they give the picking hand fingers a more natural position, but as you can see the edge of the pick is twisted in relation to the fingers. This allows the edge to hit the strings “straight” when your wrist is in its most natural position. The difference compared to a regular pick is astonishing. I made a whole bunch of twisted plastic picks with some pliers and a hot air gun that do the same thing, but they don’t sound half as good though. These bone/horn picks give a completely different sound to the guitar.

Ah - did some Googleing and found them! Dugain Picks. Can be recommended.

I was toying around with the thought of fanned frets over the weekend. It seems to me as if fanned frets would be an ergonomic feature just as well as twisting the neck - giving a more comfortable wrist position. Anyway, I will not argue for or against. When I sketched up the fanned shape, however, the shape that I had designed for this build didn’t look good anymore. I will not incorporate fanned frets in this build, but I couldn’t help drawing up some new shapes:

I have been very inspired by Rick Toone’s builds, which is pretty apparent. Almost all of these shapes build on being carved in multiple dimensions as if consisting of composite shapes that are intertwined. I’m still set to go with the original designs. Maybe the above ones will make it into a future build?

As previously advertised, I got hold of some dry composite glide bearings. I have now tested them and it all works perfectly, even though the not yet knurled knob is aluminum. Once I get the intended threads (M6×0,5 mm as opposed to the current M6×0,75) it will be even better. Here are some pictures:

I have also been in touch with ESSDE here in town about getting a bunch of these made and am awaiting to hear what the damages will be. I have also reached out to some luthiers about getting Lacewood, which seems like an interesting choice for the body. It was not available in Sweden with any of the places that I have done business with in the past. Please let me know if you have any tips.

Two things about the neck design:

1. Looking at what people who have put much more thought into this than I have have arrived at, it might not be as simple as regarding the neck as a slice of a cone when you want to twist it. Having said that, the same people tell us that the original patent was difficult to realize and filed a follow-up that simplifies matters and goes back largely to the “original” design, Burrel’s patent.
2. Secondly, again going back to the Orchid bass that I can’t seem to stop raving about, I was curious to test a trapezoidal design. One of the reasons being that it is easier to fit a square aluminum beam into a neck with that shape. It is not easier when the neck is twisted though, but I’ll deal with that some other time.

Luckily, it turned out that my TV Remote had a perfect trapezoidal shape! It is almost the same width as a guitar neck and it tapers from 16 mm to 26 mm at the thickest end.

Playing around with it, I did feel as if I could reach the low (i.e. top from the floor) strings more easily and comfortably with the trapezoidal shape. It felt as if it was most comfortable at the 24 mm thickness, which I would consider a little bit thicker than a normal neck at the same width, which means it would allow for a stronger neck than with a regular shape.

On the progress side, I made some adjustments to the bridge today and added a dry composite bearing from igus, which turned out great. Unfortunately, I left it at work so can’t try it with a string load or take any pictures, but I will do so tomorrow.

I thought that one could have interchangeable “headstocks” on the neck - mostly for looks, so I drew some alternatives:

I have solid alternatives but also ones made from a 6 mm rectangular bar. The headstocks would be prepared for special string fasteners that would allow running the string through and locking them with an insex screw. These would be bolted onto/into the headstock. But when I looked at the complete guitar, it was completely non-proportional. It turns out that the body is so small that it will not accommodate a full-size headstock. I created a Strat comparison for reference:

(Strat body shape borrowed from Warmoth)

So, I guess I will need to use a smaller one like the bottom right ones for it to make sense. Although, having seen the Orchid bass, I might re-design the whole thing…

I am leaning towards building the bridge in aluminum after all. First of all it will be easier for me to machine. Secondly, I got the new Stewart MacDonald catalog the other day and noticed several bridge parts in both aluminum and composites. I thought that only heavy materials like brass and steel were ever used for their sound qualities, but now I am willing to give it a go. Lastly, it will look good along with the Lace Alumitones that I am planning to use. Here are some sample looks:

If I do go with the aluminum base plate, I would have to go with something like the bottom left design with hardened steel inserts for the fulcrums. Why not make it Floyd Rose drop-in compatible? It would save creating a router template and custom parts for springs, etc.

It shouldn’t be any great news to anyone that a tapered fingerboard radius is superior to an even one. I’ve seen all kinds of radii listed, but decided to put some science to it and prove it to myself which one to go with. A fretboard can be considered as a small slice of a cone like below:

It turns out that starting with a 305 mm (12″) radius and a 42 mm wide fingerboard, matches a 406 mm (16″) radius and a 57 mm wide fingerboard at the 24th fret. This then in turn matches a bridge with a 10,5 mm string spacing, which is what I am planning. Note that the drawing is not to scale - it is just to illustrate the concept.

I sent Rick Toone an e-mail to ask him about his stunning Orchid design, which uses a fixed truss rod and a trapezoidal neck shape. The conversation appears here:

My question:

“Did you arrive at the alloy and dimensions through any science? I was thinking 7075 or 7021 T6 aluminum, which on paper is stiffer and stronger than 6063 (although, I have arrived at that fact only through reading catalogues - I am no expert.) With the twisted neck that I want, 6063 would probably be more suited than the 7*** series, so it would be good if it worked.

I am still a little concerned that the neck might flex. How have your experiences been?”

Rick’s swift response (published with permission):

“My experience with the square aluminum barstock has been excellent. Despite an almost inability to flex the barstock by hand (on the workbench), the pull of four bass strings in a 32″ scale length is enough to slightly flex the neck (less than the thickness of a business card) at the 12th fret. Astonishingly powerful. If you are building a six string guitar, the aluminum barstock would likely have unmeasurable flex. So my intuition tells me. One potential problem would be the neck thickens (as perceived by the hand) as it shifts around the axis of rotation.
I’ve been thinking of building a slightly twisted neck that rotates around a central hollow core of titanium tubing. Either a single diameter .75″ tube, or two side-by-side tubes (diameter to be determined). With such a construction I could retain the trapezoidal neck profile, yet keep a consistent neck thickness (as perceived by the hand), the length of the neck. Titanium would, however, likely have too much flex for a bass neck.”

Thanks to Rick and I will keep you posted on the progress. I got in touch with an aluminum shop today, but he didn’t have access to e-mail so will have to get there in person as soon as I can.

I have spent some time getting the body shape in electronic form and finalizing the bridge design. The headstock (what there will be of it) remains to be designed. Then I have some experimenting to do with the actual neck build.

Tomorrow I go back to work, so progress will be slower I’m afraid, but I will try to keep up the momentum. I have a couple of leads on people with proper workshops who can help with the metal work.

I have tried to revive my old logo, which entailed scanning the back of an old binder. I might have it in electronic form on some old backup CDs, but will see if I can’t get it done again.

I have been thinking a lot about what the twisted neck design will do to the stability of the neck and the truss rod. I did some sketches to see how the center of the rotation would affect the neck.

The picture above shows a twisted fingerboard seen from the short end. The leaning lines on the sides illustrate the width of a would be nut once the fingerboard had been cut to size. The way it looked at first (to the left), the axis would make a big impact. The top left image has the center of rotation where the strings would be, the mid left has the center in the center of the fingerboard and the bottom left has the center in the center of the would be neck. But if you would imagine that you lay the neck flat on a table and rotated it and then looked again from the short end, you would see the images on the right hand side. In the illustration, I have simply moved the twisted piece on the X-axis until the centers of the fingerboards align. It seems that the center of the rotation of the twist can be compensated for.

I have been pondering using a twisted aluminum T-beam to make up the neck, which was the reason for making the above sketches. As Alexander Gorm Ost explains in his blog it is easier said than done. But then it dawned on me that his approach of bolting the horizontal beam to the vertical would allow building a “flex compensator” into the neck instead of a tradtional truss rod.

My plan was (if the center of rotation would have messed up the “axial straightness” of the truss-rod) that this would allow compensation of the flex of the neck in both directions. But since the center of rotation does not make a difference, one could use either the above design or bolt TWO beams onto the top one and route a rod between them as a traditional truss rod. Alternatively, bolt two beams onto the top using the above design - this would allow adjustment of the torsion of the neck as well! One would have to consider weight though.

I went out and bought myself a copy of the old book of formulas for mechanics that I had in school 25 years ago (glad it was still in print) and did some very rough calculations on the deformation of a neck.

Assuming a string pull of 40 kgs ~ 400 N and a distance between string and fingerboard of 2 mm, then the a torque of 800 Nmm that is trying to pull the neck upwards. The deformation f is (M / 2EI)L^2. Assuming the most basic case of a neck that is rectangular in shape, the value I is bh^3/12 where b is the width and h is the height. So, let’s assume we have a rectangular neck that is 5 mm wide and 15 mm high. This gives us I = 1406. For aluminum, E is 70000 N/mm^2. L, the length of the beam (i.e. neck), is 490mm. f = 800 * 490^2 / (2 * 70000 * 1406) = 0,97 mm. So, an aluminum beam 5 wide and 15 mm high would be bent about a millimeter by a set of .009 - .042 strings. It looks like it should be possible to create a neck without truss rod with reasonable comfort. I will do some more calculations though, before deciding… For instance, a 10×10 rod would be deformed 1,64 mm, which is way too much.