Coarse tuners part 3

As mentioned in this post, I am trying to make a set of coarse tuners, compact and light, for use with my fine tuning bridge, allowing me to ditch the headstock. The first version used T-nuts, but this time, I made a brass plate with threaded holes to hold the tuning pegs. I have also managed to lower my failure rate in drilling holes in the tuner pegs (which are blind screws). Now I am down to around one broken drill bit per finished peg. And I've made twelve of them, six short ones and six long ones. Progress!

It's all mounted on the guitar I use for experiments. And it works. It works well, actually. Stringing up - especially getting and keeping a correct length of the string ends through the peg holes - is a bit troublesome, but I believe that once I've done it a couple of times, it'll be almost as easy as with a traditional set of tuners. The coarse tuning itself is easy. The tuners are sufficiently precise, and the fine tuners of the bridge do the more delicate tuning.

Once I've used the system long enough to believe that it works in the long run as well, I'll cut off the excess headstock and shape the remaining part - plus the brass plate itself - in a more elegant way. I will also tidy up the recessed holes for the allen nuts on the back of the headstock - those are the nuts that fix the peg when the correct note is reached. Plus, I will also buy get some prettier nuts. The ones I used are modified from those that you use for assembling IKEA furniture (Zachary isn't the only one building IKEA guitars ;-) The allen nut on the far left in the picture is for mounting bicycle brakes and I am going to get some more of these.

I also intend to recess the screws that hold the brass plate to the headstock and perhaps some time in the future, I will do a galvanic etching on the brass plate. It seems that I'm not even half way with this small project yet. Meaning that lots of fun remains.

To-do list - Status

I am having slow progress on the T-beam bass (remember the to-do list?). I have carved out the curves for neck and body on the aluminium beam using hacksaw and file. There is still some filing to do before I mount the mahogany sides, which will also have the same bottom shape as the T-beam.

Time to buy a decent plane and spokeshave.

And to learn to use them.

Coarse Tuners part 2

As described in an earlier post, I've tried to make a compact set of coarse tuners to go with the fine tuners on my Schaller 456 fine tuning bridge, so I could reduce the headstock and loose the big and heavy traditional tuners. The earlier attempt in the form of a locking nut wasn't succesful, but now I think I'm on to something.

I've installed my own coarse tuners, each consisting of a blind screw, a T-nut and an allen nut (a.k.a. an internal wrenching nut). In the blind screw, a hole is drilled for the string to go through, just like the peg of an ordinary tuner.

To tune up the guitar, you turn the blind screw clockwise with an allen key until you reach the approximate tone. Then you fasten it by tightening the allen nut on the back of the headstock. The rest of the tuning is done with the fine tuner at the bridge.

One of the beautiful things about it is that when you tighten or loosen the string by turning the set screw, the height of the string over the fingerborad stays the same, since it rests in the screw's thread. And the pull of the string tightens the allen nut against the T-nut, securing the string even more.

The best thing about it is, it seems to work perfectly. And it's much smaller and lighter than ordinary tuners, so it's a good solution if you want to build a headless guitar - or convert an existing guitar to one. You'll have to leave a little bit of headstock for the T-nuts, but that's not much. And you might want it anyway to stop your fretting hand from sliding off the neck.

On my own guitar I've mounted the tuners on the very end of the headstock. The reason is that I'll be using the other sections of the headstock for experimentation with alternatives to the T-nuts. A set of threaded inserts and a brass plate with threaded holes are some of the things I want to try. Next experiment will probably be threaded inserts mounted on the next section of the headstock. And I imagine that when I have reached the last section of the headstock, next to the nut, I'll know which of the solutions I prefer.

Drilling the string holes in the blind screws was a pain. I only got two made before I had dulled or broken my drill bits. I'll have to buy some new ones and do it right. That's the reason why the remaining four strings in the picture go to traditional tuners.

Btw, I imagine that if you add some loctite or similar to increase friction, you might be able to do away with the allen nut. Afaik, there also is a substance called "peg dope". I have to get some and try if the tuner can hold the string without the allen nut.

To-do list

Nothing much has happened on my T-beam-bass lately. I've replaced the jack connector since the old one didn't work and clamped the connecting cable going from the jack more securely to the sliding bracket. Plus, I've borrowed a friend's bass to do some comparisons of sound, feel and ergonomics.

His is a 34" bass, and though the picture doesn't really show it, mine, with its 30" scale length, is much smaller and lighter.

My bass still isn't exactly pretty, but I do intend it to be so one day. But until now (and probably some time ahead as well), most of my focus is on experimentation rather than looks.

Nevertheless, in an attempt to convey an idea of what I expect it to become some day, here's a list of some of the things, I'd like to do next:

• Make the saddles lengthwise adjustable for intonation, i.e. making slots for the saddles and fastening them with nuts.
• Shape the neck as shown on the image . I have to modify the sole plate of my jigsaw to be able to do that.
• Make a prettier and more ergonomic shield in 5 mm acrylic (that's approximately 0.2"). The current one is just 3 mm thick, and it's too fragile and flimsy looking.
  
• Make mahogany sides rather than the current spruce ones. What's keeping me back here is that I'm not quite sure yet where the holes for the shield are going to be, and I'd rather keep the mahogany intact and experiment on the spruce.
• Decide whether I like the sound of the vertical pickup. If so, I'll tidy up the bracket. If not, I'll buy a P-bass-pickup and use one half of that in a new bracket.

I am not alone

One of the good things about the T-beam bass or guitar is that it's fairly easy to build a functioning instrument and improve it from there. In spite of its relative simplicity, there's still lots of challenges in it. If you're ambitious, there's plenty of aspects to improve. If you're not, there's still the joy of building your own functioning, albeit crude instrument.

It's a really good project in many ways, but until recently, I thought I was the only one making a T-beam bass.

To my delight, as I discovered here, I am not the only one. Kaspar Torn is building one as well. It's still in its early stages, and so far, it looks very promising. As you can see from the pictures, it differs from my own project in a number of ways:

Strings are anchored in a bolt through the vertical flange

String slots and zero fret

Tuners upside down

Angled tuners

This project is going to be interesting to follow. Kaspar leaves many options open, such as a detachable acoustic body and a spike, allowing it to be played upright.

I will post updates as the project moves along.

A slightly prettier sliding bracket

I've made a sliding bracket for the small pickup. It slides with little effort and easily picks up the different antinodes of the strings. Unfortunately, the pickup itself doesn't sound that good, so one of the next steps might be mounting one half of a P-bass pickup in a similar bracket - or perhaps have two sliding brackets and the usual switching arrangement.

Trying a good, well-known pickup should give me an idea of what the instrument sounds like and make it easier to find out its particular characteristics.

The system of cable and female jack on the body also works fine. I plan to add tone and volume pots down by the jack at some point.

A body that preserves vibration

With the addition of a body to the T-beam bass, it begins to resemble an instrument.

The body is a 3 mm (around 1/8") acrylic (or plexiglass) shield, cut with a saw and an angle grinder, polished, and bent in shape with a hot air gun. As with almost everything else on the bass, it is not intended as the final version. For this, I will use thicker (probably 5 mm) acrylic sheet and have the leg rest further to the back.

The acrylic shield is slightly bowl-shaped so it follows the contours of my body. It's a fairly deep bowl shape ;-) It has a leg rest bent into the lower part and an arm rest created by folding back a wing on the upper part. It quite looks like the body of an Ovation Breadwinner, though that was not the intention originally. It's very comfortable, and I expect it to be even more so when I've moved back the leg rest.

The four mounting supports that connect the shield to the stick will have to be replaced with a central support mounted on one of the two places where the stick has least vibration. A so-called node. I located the node by suspending the stick on two springy foam blocks, pouring salt on the stick and tapping it with a knife handle. As predicted in the marimba literature, the salt would gather to show the location of the node. Luckily, the node is somewhere in between the mounting supports, which makes construction easy. BTW; marimba and vibraphone builders do a lot of interesting research into the acoustics and vibration of wood; something that the guitar builders might draw upon in their work.

The reason for having the shield mounts on the node is to preserve vibration in the stick and not have it travel through the body and into the all-absorbing torso of the player. The node does not vibrate - or at least it vibrates less than other areas of the stick, meaning that less vibrations will be transferred from this point to the shield than from any other areas. I expect it to have a pronounced effect on sustain, and perhaps also on tone.

Some sort of leaf spring suspension mount might give even better isolation between the shield and the stick, but that will have to wait for a later version.