Saturday, 30 June 2007

Bridge and tuners for the headless design

Having settled on a headless design, one of the next questions was which bridge and tuners to use. A small number of bridges with built-in tuners already exist, e.g. the ABM or the Steinberger. Unfortunately, they are all fairly expensive, and it was a fun challenge to try to find a cheaper (and perhaps better) alternative.

One of the first ideas was to mount traditional tuners at the bottom as shown in my previous post "The Ergonomic Guitar". To make room for them all - plus the fingers when tuning - the bottom end of the guitar would have to be cut at a quite steep angle. That actually looks quite good and fits well with the idea, that the body should support the right arm (assuming you're right-handed). The T-beam can extend into the upper wing in an elegant way.

Unfortunately, the angle of the end of the T-beam had to be *very* steep to allow for room for all the tuners. An alternative would be to use string trees to guide the strings to each tuner - the strings would then spread out from behind the bridge as they do at e.g. the Kramer Duke (which happens also to be an aluminium guitar with the neck going all the way through).

To get a cleaner look and ensure sufficient downwards pressure on the saddles, one could improve this design by letting the strings dive down behind the saddles and continue on the backside of the guitar on to the tuners. To avoid to much friction when tuning, it would probably be necessary to use a very slippery material for saddles and for the material on the bottom, on which the strings rest.

On the picture, you can see that I chose to let the saddles rest directly on top of the T-beam instead of on a bridge plate. I assume it will improve sustain.

On Building the Ergonomic Guitar, a couple of headless guitars using Steinberger Gearless tuners have been described. Todd Keehn and Scott French have used them. Unfortunately, they both mount the tuners the way they're intended, meaning that the strings run on top of the guitars and into the tuners. That means that you'd have to reach to the back of the guitar and feel your way to the tuner in question. It works fine on a traditional guitar where the tuners are mounted on the guitar's head, but for a headless guitar, I believe it is not very practical.

If the Steinberger gearless tuners were mounted upside-down and the strings were routed below the surface of the T-beam (as in the earlier described idea with traditional tuners), the knobs would be on top of the guitar where you could see them. That would make for a clean design and improved usability.

The picture above shows the guitar (without the wings) using this configuraion. Furthermore, the separate saddles are replaced by a custom cut one-piece bridge made from TremNut or a similar low-friction material. That means that the bridge has a fixed intonation like the Les Paul Junior bridge and those on some PRS guitars. I like the idea of these bridges: The less separate parts, the better sound.

Besides Building the Ergonomic Guitar, The Project Guitar site - and especially the forum - has been a great source of inspiration and information. On the forum, a number of alternatives to traditional headless bridge/tuner combinations have been proposed. Among these, there were two, which I found especially interesting.

One of the regular posters had made his own tuners with separate saddles for a bass. With a little modification, this principle lends itself very well to the aluminium T-profile: You can mill six grooves for the tuners and saddles in the top flange of the T-beam - as shown in the picture below.

The knobs are in two planes, as this allows for bigger knobs and therefore easier tuning than if they'd all been in-line. That would be a really nice way of taking care of tuning. Unfortunately, I have almost no experience in metalworking (cutting the T-beam into shape is in itself a daunting task), so this idea will have to wait for later.

Another of the regulars at Project Guitar had used the Schaller 456 fine-tuning bridge for a headless travel guitar. The fine-tuners can't go very far, but he uses a string-mounting procedure with a pair of pliers and a locking nut, ensuring a sufficiently precise tuning when tightening the string with the pliers. The fine-tuners do the rest of the job. I've settled for this solution for the prototype of the T-beam, as it involves relatively little and uncomplicated metalworking as compared to the other solutions.

A very rough sketch looks like this:

I've bought the bridge (as well as some other components), so now that's settled. At least for the prototype. I'm especially keen on trying the Steinberger Gearless/TremNut fixed-intonation bridge combo on a later version. But as this is my first guitar project, I want to reduce the number of things that can go wrong, and the Schaller fine-tuning bridge offers a proven combination of bridge and tuning.

Wednesday, 27 June 2007

Guitar Ergonomics

The classical Guitar

Back in the old days, before we had electric guitars, a guitar looked like this:

CC Martin Möller, Creative Commons Attribution ShareAlike 2.0 Germany, resized by me

It's beautiful and sounds nice, but it's not particularly easy to play.

There probably exists a number of very good reasons for this unhandy shape and size. Being totally acoustic, the guitar needed to have a large body. The tuners had to be at the end of the neck, as mounting them on the thin and acustically crucial soundboard would probably have been out of the question. Why the body had to have the shape of a rather large figure eight is beyond me. It probably has to do with acoustics, too. Alternatively, the reason mighe be that it makes it easier to rest the guitar on your thigh - and for symmetry reasons, the other half was shaped accordingly.

When technologies evolve, they often retain some of the drawbacks of earlier versions. Probably because many designers (and customers) are quite conservative and don't like things to depart too much from what already exists. Early automobiles, for example, resembled horse carriages to an unnecessary degree.

The Electric Guitar

I think the same effect is in play for the electric solidbody guitar. At least when looking at the most well-known brands and models such as Fender, Gibson and PRS. It still has a head at the end of the neck, even though it tends to make the guitar neck heavy and always hits other objects and people when you move the guitar around. It still has a rather large and thick body, though acoustics do not come into play any longer. It still has the shape of a fat figure eight, albeit with cutouts at one or both sides for easier access to the higher frets.

To me, the bottom cavity of the figure eight is in the wrong position: If i have it on my right thigh, it feels too much to the right and vice versa. A cavity located nearer the bridge would be more suitable, as resting the guitar on the right thigh would give a usable position. At least, so I think. Regarding the other inherited features from the classical guitar, I'd like a thin guitar allowing my playing action to be close to the body, a compact guitar with no head for knocking out the teeth of other band members, a light guitar that don't break my back.

The Ergonomic Guitar

Hence, one of the early decisions in the desigh of the T-beam prototype was to go for a headless and ergonomic design. On Building the Ergonomic Guitar, there is a lot of discussion on suitable shapes and design principles, plus articles on some of the smaller luthiers, who build ergonomic guitars. Especially the Klein guitar shape caught my attention: It simply looked like it would be easy and relaxing to play.

My design will be something like this. The exact shape of the wings may vary. I might experiment with several shapes and woods for the wings. But overall, this is what it will look like. I don't try to make it look like any particular one among the existing ergonomic guitars, but I think the Forshage electric guitar is the one it's going to resemble the most. The Forshage, in turn, is inspired by the Klein, BTW.

The picture of the ergonomic T-beam guitar is an older (i.e. around two months) design. I later abandoned having the traditional tuners at the bottom of the guitar in favour of a different desing, instead using a bridge with integrated fine tuners. More about these considerations in a later post.

Background - why and how

Over the last years, I've become more and more interested in building guitars rather than (just) playing them. I never got around to actually building anything, but I took a couple of guitars apart and put them together again. I also discovered, that people build guitars in aluminium (or aluminum, if you prefer). They sound great. I'd like to have one, but they're prohibitively expensive.

One evening a couple of months ago, when i was looking at, which links to a lot of aluminium guitars, it struck me that the majority of guitars have wooden bodies with aluminium necks or aluminium bodies with wooden necks. There were comparably few one-piece aluminium guitars. And no aluminium "neck-through"-necks with attached wooden "wings" at all. That puzzled me a bit, because it seems that among luthiers using wood, the neck-through design is widely considered the best overall solution.

I tried to imagine how an aluminium neck-through-neck would look. It might be made from a single long slab of aluminium. That would be very heavy, so you'd probably route out some of the material along the neck like the Kramer aluminium neck. Then you'd get something looking a lot like an aluminium T-beam. You know, these metal beams used for load bearing parts of houses among other things.

Why not use a stock T-beam? That'd be way cheaper than having the neck made from a big slab of aluminium on a CAM router. I think it can be done in the following steps.

You start out with at T-beam, which will act as sort of a spine in the guitar. A top flange of 100mm, a bottom flange of 60mm and 5 mm flange thickness (that will be approx 4, 2,4 and 0,2 inches) will be suitable. They are available, but - as it should turn out later - not exactly readily available.

The T-bar is cut to shape (Pickup holes, neck and head). Due to the width of the pickup holes, the T-bar has to be quite wide in order to keep its structural strength. With a narrower T-bar, the pickup holes would completely intersect the top flange, weakening the T-bar considerably.

Having modified the T-bar, you screw or glue on wings (like on a wooden neck-through guitar), fingerboard and some pieces of wood to give the neck its desired shape. Plus, of course, route out cavities for electronics, sand the body, mount bridge, nut, etc, etc.

This way, you get a guitar with a lot of structural strength from the T-beam. You have great freedom of choice of wood and shapes of the body. And best of all: It should be possible to do it with ordinary do-it-yourself tools (hand held router, metal saw, sand paper, electric drill, belt sander, etc.).

I think it will work. I think it will look amazing. I am not sure how it will sound, but I am going to build myself one. Then we shall see. Or rather hear.

I'll post updates on this blog. I've already done some designing and planning plus a couple of purchases. This will be described in separate posts in the near future, and I expect that when I get around to the actual construction of the thing, my posting will have caught up, and I'll be posting in more or less real-time.