Sunday, 14 December 2008

Stick Bass Pictures

I've made the spine of the two-string, nylon string, fretless piezo alu T-beam stick bass. Now I have to stick some wood and some piezo pickups on it.

Some photos:

I will shorten bot ends of the T-beam down to the tuners and string holes. Btw, these are not nylon strings as originally described, but flatwound steel strings. I found out that the pull of nylon strings wasn't that much lighter than that of steel strings, so I went for these instead.

I've played it with a cheap non-preamplified piezo pickup on the flange. Sounded very good and feels very alive... I'll make some sound samples to go here. It even sounds good bowed. Plus it was easy to bow; since it only has two strings, they are easy to hit even though the fingerboard is flat (as in not being "radiused" like the fingerboard of e.g. a violin). So far, I am really, really satisfied with it.

Common bass tuners mounted in oak blocks. Bronze saddles through top flange. And yes, the saddles aren't completely perpendicular to the top flange. I'll mount them in slots in the top flange rather than in threaded holes, which will make it possible to adjust intonation. And then I won't have to worry about my crooked thread-cutting.

Action is ridiculously high at the moment, but if I set it lower, the strings don't press properly down on the saddles. I need a string tree, but I'll make it myself, since the strings are 18 mm apart.

Making the wood sides is next. Plus, I might trim down the "fretting" part of the neck to 25 mm (1") thickness. It feels too thick as it is now (4o mm). I was going to do that at some point anyway, but now I'll do it sooner rather than later.

The local staircase manufacturer kindly donated a nice piece of mahogany, and I've just bought a table-mounted circular saw. Plus, I am eager to use my router that I bought over a year ago and haven't used much. Making the wood sides should be a breeze.

Hope springs eternal.

Wednesday, 26 November 2008

Setting my sights a little lower

It can't have escaped anyone's attention that I haven't yet built the T-beam guitar. Even though I've talked a lot about it, nothing tangible has emerged. I've bought the components and there's nothing much missing. It's just a question of doing it.

So why haven't I made it yet?

It's mostly due to my busy life with a job and two small children. Yet other busy parents manage to build guitars, so there must be another reason. I've been thinking a lot about it and have reached the trivial conclusion that the T-beam guitar is too big a task for my limited experience. There are too many things that can go wrong in the process, and that's keeping me back.

I've decided that I need an easier task to gain some experience. A task that gives me a reasonable chance of success. This means that I'll have to lower my ambitions and - for starters - build something much simpler: A two-string, nylon string, fretless piezo alu T-beam stick bass. This is way easier than my original goal (a guitar with frets, tapered neck, pickup cavities, etc.), meaning that I might actually get it built.

The instrument minus acrylic body

The simplicity (and hence increased probability of it becoming a reality) of this new project in comparison with my original idea is due to the following factors:

Fretless because:
  • Fret, bridge and nut placement becomes less crucial or non-existing
  • I don't have to think about adjustability for intonation (lengthwise adjustable saddles)

Two strings because:
  • It is simpler than four strings.Whether or not to radius the fingerboard is not an issue.
  • Stig Pedersen of D:A:D plays a two string bass ;-)
  • I will be using the same basic design as e.g. Krappy Guitars and Longbow. This means that the neck won't have to taper towards the nut, which in turn means that I can use a standard T-beam and only cut it to get the desired length.
  • The few times, I've played a bass, I've mostly used the two low strings.

Nylon strings because:
  • I like playing nylon strings
  • They put little tension on the neck, meaning that I don't have to install a truss rod.

A bass because
  • I want to build something simple, and a two string guitar doesn't appeal to me.
  • I don't want a fretless guitar. At least at present, I want my guitars to have frets and six strings.
  • I don't have a bass, and I could use one. There's a good chance I might actually play it.
  • I believe the human ear to be less sensitive to tonal precision in the low register. Therefore, fretlees is a more nearby option for basses than for guitars. On a guitar, it would be very, very obvious if a tone was even slightly off, whereas on a bass, your ears would be more error-tolerant. On a bass, there is a larger margin. And I can use that ;-)

Piezo pickups because
  • It will serve as a testbed for my preamp/buffer experiments (thought I might swap some components when using them for guitars rather than basses)
  • I want to be able to use nylon strings, and a magnetic pickup won't pick them up (unless they have steel cores, which would increase neck tension)
  • I can use a much narrower T-beam than if I'd have to make room for traditional pickups and still avoid the top flange of the T-beam being completely intersected by the pickup cavity. Narrower means being able to use a standard 60 mm aluminium T-beam.

Alu T-beam because
  • It gives me practice in building T-beam guitars, which is what I set out to do in the first place.
  • It gives me the opportunity to experiment with mounting the piezos in different wood species on the quarter circle neck "sticks" (e.g. maple and mahogany).
  • Using semi-hollow wooden "sticks", it allows for wiring and piezo placement in an enclosed space everywhere on the bass (headstock included)
  • It gives me a reasonably hard fingerboard surface (depending on the alloy and temper), which is important with fretless instruments.
  • The considerable thermal expansion and contraction of aluminium doesn't ruin intonation when the bass is fretless. On a fretted instrument, this is a problem. This makes aluminium a more suitable building material for fretless than for fretted instruments.

A stick (with detachable body) because:
  • I believe that the body dampens the strings and reduces sustain. It's not so much the guitar body itself, but the fact that it rests on the player's torso and the player's arm rests on it. If you isolate the body from the neck (or "stick"), it will be able to vibrate more freely and without damping.
  • It also allows a lot of freedom in designing bodies with ergonomics or looks in mind. The stick remains, but you can swap body according to your playing style and physique. Or your mood, for that matter. Plus, you can experiment with many different shapes and materials for the body. You can have a guitar body designed for seated playing and one for standing up. One for resting the guitar on your left thigh, and one for resting it on your right, depending on preferences.

That's a lot of reasons to build the thing. Some are better than others, but overall I believe the project to have a good chance of success.

Thursday, 4 September 2008

A locking nut that didn't work

Since I put the T-beam guitar on hold for a while, I bough a cheap Gibson SG copy for various experiments. One of the first things I wanted to try out was a tuning system, which uses a locking nut in combination with a Schaller 456 fine tuning bridge

I need to be able to rough tune and lock down each string separately, so the usual ones with two strings per screw won't do. According to the idea, after rough tuning, the fine tuners in the bridge take care of further adjustments.

For some time, I've been looking for a suitable locking nut. After a while without identifying anything useful off-the-shelves, I decided to make one myself.

I started with a piece of 7075 T6 aluminium. I drilled six holes for the string locking screws and two for screwing the locking nut on the headstock. I then threaded the holes (M4).

I then made six grooves; one for each string.

...and filed the grooves smooth.

I mounted it on a piece of brass on the headstock, but the D string snapped when I tightened the screw. On closer inspection, the screws turned out to have very sharp edges, which explains why the string was cut. I'll have to file the ends of the screws flat. I'll have to shorten them a bit anyway, so that's no big deal.

Unfortunately, there was another problem as well: The pressure of the screws lifted the nut off the brass plate (the picture shows the gap between the aluminium nut and brass plate). That can probably be solved by making the nut a bit deeper and having two mounting screws on each side of the string locking screws rather than only having one set of screws.

I'm going to give it another try some day and make an improved version.

Btw, if it had worked, I would have bought six proper set screws for it and cut off the remaining headstock. In an artistic fashion, of course ;-)

Thursday, 14 August 2008

I haven't abandoned the T-beam guitar

...but I've put the project on hold for a while. I've been too busy the last half year or so to really focus on building guitars. Plus, I've found out that there is a number of areas - especially metal working - where I need to improve my skills and learn new ones.

On top of that, there are many things about guitars besides building the neck and body, which I'd also like to do. New types of bridges, new tuner systems, piezo pickups, etc., etc. These are mostly ideas that the design of the T-beam has lead to. For example, I need a locking nut for it, but since it's headless, I can't use the usual ones with three screws, each locking two strings. In order to roughly tune each separate string with the nut (principle described here), I need one screw for each string. Such nuts exist, but they are all narrower than the intended neck width of the T-beam. Meaning that I'll have to try to make one myself.

I did. It didn't work. I'll probably describe this failed attempt in another post and try another approach.

As mentioned, there are other issues besides the locking nut, all adding up to the guitar being a huge task with too many variables for an inexperienced builder as me. Therefore, I am going to fool around for a while, having fun trying out various ideas, hopefully gaining knowledge and skill in the process.

As a testbed, I've bought a cheap Gibson SG copy on which I plan to do some modifications and try out some ideas. This way, I can expriment without ruining anything valuable and have a functioning guitar on which to test the practical usability of the various parts that eventually will go on the T-beam.