6 mm body, new forearm and thigh rest

Even further progress

 The two-layer neck guitar is progressing further. Now, it's a very nice, compact and well-sounding instrument. There are still improvements to be made, but now that it's playable, I hope to play more and modify less.

The neck is very flat (as Rick Toone's Exoskeleton neck) without any wood on the back. I might add a piece of wood to make the neck thicker and more familiar, but for the time being, playing the thin neck is fun and works surprisingly well. My thumb still creeps up over the edge of the neck, and that's not the proper way to play it. As long as you play with the "correct" classical grip with your thumb behind the fingers, having a thin neck feels fast and precise.

I've mounted two of my "current transformer" or CT pickups on the guitar. There's not enough room underneath the strings for a traditional pickup. The CT pickups work in the same way as Lace's Alumitone pickup: The part beneath the strings is the primary coil, which is connected to the secondary coil (the current transformer), which is at the side of the main aluminium beam. Magnets are small cylindrical neodymium magnets mounted in hex blind screws. Since there's only one or few primary windings under the strings, such pickups can be made very flat. This in turn allows me to keep the whole instrument rather thin, since I don't need deep pickup cavities.

On my neck pickup, I use a brass coil with only one primary winding (made from a 20 x 3 mm brass bar) connected to a secondary coil by an iron core (the green florist's wire). The secondary coil is home made using a sewing machine bobbin. The bridge pickup has about 15 primary windings running through an AS-104 current transformer. They supplement each other well, the bridge pickup being quite snappy and sharp, while the neck pickup is more deep and soft.
 
Both pickups have low impedance; in the range of microphones, which is why I am using an 500 ohm -> 50.000 ohm line transformer before plugging the guitar into my amp.

Also added is a string retainer at the headstock end, keeping the strings from rattling. A bracket for jack, volume pot and two mini jacks for the pickups makes it easy to plug it into an amp and to switch the pickups. For intonation, I've added a couple of screws to the saddles going into the end piece that holds the tuners. By turning the screws, the saddles are moved back and forth.

I still haven't added piezo pickups, partly because I haven't figured out where to put the pre-amp and controls, partly because the CT pickups function so well.

Next step might be a thicker (6 mm rather than 4 mm) plastic body, this time bent with a little more care. The one I'm using now has been bent into shape using a heat gun and brute force. Another improvement could be a piece of wood on the plastic body that acts as forearm support - the curve of the body makes it hug the torso of the player (which is nice and gives good control of the guitar), but there's nothing on which to rest my arm, and that becomes a bit tiresome.

There's only one aspect that I'm not quite satisfied with: The bow of the neck is not easily adjustable. This is due to the strength of the beams - even without tightening one against the other, the pair of them are enough to counteract the pull of the strings, so there really isn't much to adjust. A solution could be a thinner back beam, but I am not sure they are available in the necessary width.

Further progress on the two-layer neck

Improvements since last post:
Saddles modified -> lower action
Transparent plastic body (styrene-acrylonitrile) added.
Two screws at the bottom side of the head end holding the two layers of the neck together.
Row of neodymium magnets in M4 blind screws for current transformer pickups.

Future improvements:
String guide - pressing down on the strings before the zero fret, since they tend to rattle.
Row of magnets for current transformer pickup in bridge position.
Screw holes making the saddles lengthwise adjustable for intonation.
Piezo pickups and amplifier.
Jacks, switches, pots etc. I plan to put the electronics on the plastic body rather than on the beam itself.

Progress with the two-layer neck

Still much fitting required, but it's playable and tuning works well. Neck tension needs attention; the two beams don't have sufficient contact at the headstock end.

Two-layer aluminium neck

Among the drawbacks of my old T-beam designs were the lack of a truss rod or similar system to control the bow of the neck.

A way to help this - but still use stock aluminium beam for the guitar - could be having a neck in two layers - an upper flat beam, tightening itself by pulling on a similar lower beam.

I hope the picture explains it, but in case it doesn't: The design uses a screw being retained by a bracket attached to the lower side of the top beam. The screw goes into a threaded hole in the end of the lower beam. When tightened, the screw will draw the top beam downwards, counteracting the pull of the strings.

With this build, I'll try if it works. The upper beam is only the length of the neck. It has frets mounted directly into it. The lower beam extends into a narrow body.

On the bridge end, I plan to mount a "stick-and-screw" tuner system. The prototype shown here works decently. I imagine, that using a brass bracket rather than the aluminium one here as well as harder steel for the screw threads will improve that.

The nut end contains a brass bar for holding the string ends, plus - on the bottom side - a bracket for the screw, that tightens the neck against the strings' pull.

Today, I cut the fret slots in a home made miter box and mounted the frets. The glue (two component epoxy) is hardening at the moment.  Tomorrow, I shall see how well it turned out.

Next steps will be making the brass bar and bracket for the nut end plus drilling the screw hole in the lower beam.

The Bobber - the black SG is further reduced

My black SG has had to go through further alterations. I am trying to see, how much you can modify a stock guitar into something ergonomic. Since cutting away is easier than adding on, i've carved a "shark bite" for thigh rest. It allows the guitar to be balanced in a classical playing position with the neck pointing upwards.

On the bass side, I carved a concave area for the strumming/picking hand. It does away with the sharp edge and makes it easier to hold the guitar.

Both were covered in damp-shaped leather, fastened with epoxy glue and copper tacks.

The shark bite made it necessary to relocate the controls, so I added a series/parallel switch mounted in a slanted copper pipe end cap. The jack enclosure is from copper tube and brass plate. The volume and tone knobs are located in what's left of the original control cavity.

The tip of the bass side horn was replaced with a brass one, while the length of the treble side horn was reduced considerably and topped off with a brass cap.

I am going to abandon the new coarse tuner system for now, so next steps on this guitar might be tidying up the headstock brass plate and remount the old high e coarse tuner.

Improved thigh support

The Lectus Testus has gotten a more adjustable thigh support. The fine-adjustment screw might be over the top... there's a limit to _how_ precisely you need to adjust it, but it _is_ a testbed (and it all is a hobby and supposed to be fun), so on it went anyway. The thigh support was twisted slightly in relation to the body of the guitar. Now it better follows the curve of the player's hip when sitting.



Also added was a treble side horn, giving the player the option of resting the guitar at his thigh in a "traditional electric guitar" style. Unfortunately, the thigh support is now in the way of the flexible outer cables that went from the side of the body to the thigh support, so they had to go for the moment. I might relocate them to the other side of the body.

The whole instrument functions nicely as a playable testbed. It has begun to develop some rust on the steel body, so polishing and bluing might be some of the next steps. Tuning is acceptable, but not extremely smooth. Filing and lubrication should impove that. If not, I'll have to use finer thread (M4 X 0.35).

Coarse tuners part 5

The coarse tuners that I made for the black SG with the Schaller fine tuning bridge were - after all - too troublesome to string and adjust. I've made another attempt, this time consisting of
- a hex screw going through the head plate,
- an acorn nut with a hole for the string and the top cut off,
- and a hex blind screw going through the top of the acorn not, securing the string against the end of the big hex screw.

All screws have been shortened and filed flat at the end. Many other tubes, screws, etc, can be used. The string is secured at the bridge end, inserted through the hole of the acorn nut.

It seems to work nicely, but I'll have to make some more and try different string gauges.

New tuner, bridge, jack and tubing

This last month I've been improving some details of the testbed guitar:

The tuner has been changed to my slider-based design. It is mounted on an angled plate ensuring that the strings have sufficient break angle over the saddles. The angle also keeps the sliders in contact with the plate. I've used six modern strat style saddles for sliders - when I get around to it, I'll make some better (and prettier) ones from brass. Using the right screw hole for securing the string ensures that the pull of the string tightens the screw. It's got more travel than I need, so I'll shorten it around 5 mm. The knurled knobs are standard DIN 466 brass knobs. I've used two for each slider so the fingers have more grip surface. They're interlocking with one another, giving great utilization of the existing space, but making it difficult to remove one without loosening them all.


The tuner works very well. The grooves and lid that you see on most other headless slider based tuners aren't necessary, as the string pull keeps the slider oriented lengthwise. When I get some tools for making fine thread (M3 and M4 x 0,35), it'll be even smoother.

The bridge is an improvement from my earlier design consisting of two saddles each holding three strings, but is a bit simpler: It is reversed, being fixed to the body in front of the contact point of the strings. This gives me a shorter overall design, allowing for the tuner to be placed closer to the bridge. 

Action is set by lifting or lowering the saddle with the small blind screws in the bottom and then securing with the big inner hex screws. Intonation is set by turning the blind screws going through the vertical flange of the saddle (they press against the big hex screws).

The jack holder is a copper pipe cap - thanks Martin for the brilliant idea. I'll use them for swithces and potmeters as well. The copper tube holds the wires, shielding them from electrical interference. The flexible cable is a piece of gear cable outer tubing back from the days when I was racing bicycles. It allows for the thigh rest to be moved and turned.

It is common among some luthiers to give their guitars a name. Since it's a testbed, and bed is called Lectus in latin, I'll call it Lectus Testus. Yes, it's rubbish latin, I know. And yes, it might actually mean something different.

Added: I just weighed it: 2,5 kg as it is now. That's not too bad.

A guitar that works

What started as a testbed has turned into a nice, playable guitar.

For the first time, I've made a working guitar that I believe suits my position and style better than anything I could buy. This was the problem, that initially, some four years ago, got me interested in ergonomics and the possibility of building your own, very personal guitar.

That's something of a milestone, actually.

[Blogspot insists on rotating the image on the right. I have no idea why, and I can't fix it]

Things I like about the guitar:

It's comfortable to play. There's still much adjustment (and probably replacement of some wooden parts) to do, but it's more comfortable than any other guitar that I've played.

With the Seymour Duncan pickup, it sounds at least decent. My first impression is that it's a bit shrill, probably due to the steel body.

It's modular, meaning that I can replace components when I want without taking the whole guitar apart.

It's easily adjustable, making it possible to try different positions.

It's thin where it matters ...the area of the body around the bridge pickup hole is only 20 mm thick. And that's the place where it matters, because this is the area with which the guitar rests against my chest. This means that I can have it close to my body without having to reach my arms around it.


Everything on it works. Tuning, intonation, action, pickup adjustment, neck bow, etc. Some parts work really well (the bridge and wooden arm and thigh rest), while some could use improvement (the tuners and the strap horn).

The roughness and homemadeness are style elements, which are imposed by my lack of workshop skills (and the fact that I don't much like to spend money on having a professional doing it for me (because if you spend money, you have to work more, and I'm not particularly fond of that, either)). But I've come to like the roughness and the fact that you can see that the parts are made from stock metal. There's a certain honesty to it.

Things I'm doing these days:

• Playing the guitar
• Tuning the guitar (I'm dissatisfied with the tuner system, but it works well enough for now)
• Moving and adjusting the wooden pieces
• Adjusting action and intonation. That's pretty easy on the two part bridge, but I am going to make an improved version with the saddle piece at the rear, and fixing and adjustment screws towards the neck. That'll give more room for the new tuner.

Things I might do next:

• Add some copper tubing for the pickup wires. 
• Copper jack cover plus master volume and switch. I plan to use the principle of copper "cups" that Rick Toone made.
• New tuner system (see picture)
• New bridge
• Make a wide copper pickup cover that covers the bridge cavity.
• Shape and smooth the wooden pieces. They're quite rough and lack a common "theme" of shapes and curves.
• Blue the body
• Test my current transformer pickups on the guitar (after all, it's thought out as a testbed)

But first, I have to buy some more tools and some more metal.

Adding brass and wood

Got the steel box straightened and reinforced plus the arm rest, leg support and strap horn carved from scrap mahogany. It's all in a very rough state, but I expect it to be ready for neck, bridge, tuners and pickup in a week or so.

It's very easy to adjust or move the wooden pieces to allow for different playing positions. That can be useful when making other, less modular, bodies at a later time.

I'm considering a rustication process for certain areas of the wooden parts, but I have to get the guitar playable first.

Room for pickups

I decided to put one or two good pickups in the testbed guitar. My original idea was that it should be kept playable at all time. But I was too busy trying out my flat pickups to get a proper pickup mounted. I hoped that I would make a pickup that sounded great, but I'm not sure if I'm satisfied with their sound (more on that later).

I needed a good pickup for the guitar to sound decent, but also to have a sort of reference: something to compare with when trying out the various pickups. I decided to go for a couple of Seymour Duncan pickups, I bought for my first T-beam project, but later put in my strat.

The pickups are wider than the T-beam, so in order to fit them in, I had to cut through the sides of the steel box profile. That was easily done with an angle grinder (my favourite tool these days, with cutting disc as well as flapdisc for shaping wood).

So far, so good. Unfortunately, that put quite a bow in the box profile. I didn't count on that (only thought wood behaved that way), but I suppose that's part of learning.

That's put rather a halt to my progress. I'll make some brackets and beams to straighten and support the box profile in its weakened state. I was going to make pickup holders anyway, but now they're also going to add strength.

Btw, I'm condidering this oil bluing process for the box profile. And, I'm making some mahogany forearm and thight supports (and a strap horn), so I can ditch the acrylic body, that I've grown a bit tired of.

Truly headless

After postponing it a number of times, I cut off the strat headstock of my very fine Warmoth neck. That took a bit of self persuation, but I needed it headless. A brass angle bracket is holding the strings. I also made a new acrylic body. This time, I tried to make it really fit my torso. I tried too hard: Most of the curves and shapes are too pronounced and it's actually too tight on the body.

Bridge and tuners are the same as in last post. I plan to make an improved version of the tuner bracket (or perhaps abandon it in favour of one using my plunger type tuners).

The pickup is a P90 mounted above the strings. I plan on experimenting with a couple of experimental pickups using primary coils with few windings and a current transformer, but I haven't gotten around to that.

It still needs a strap to be really comfortable.

Things I might do next:

• Make a steam bent plywood body in the style of the acrylic ones.
• Make a new and more ergonomic acrylic body.
  
• Make a proper wooden body for the neck and ditch the rectangular steel tube for a while.
• Test and develop my pickups.
• Get back and properly finish the two-string bass. This involves adding a slidable pickup and a piezo-pickup with preamp.

Two piece brass bridge

The strat type hardtail bridge that's on the developing testbed guitar was in many ways a temporary solution. Tuning lacked smoothness and precision with the strings going through the holes in the bridge plate on their way to the tuners. Also, it looked out of place - being chrome plated as well as being wider than the rectangular steel tube it was mounted on.

The bridge that replaces it is made from a brass U profile. It's height adjustable. To achieve acceptable intonation of all strings, it is divided in two. This makes it possible to adjust the wound bass strings and the unwound treble strings in two separate banks of three.

It seems to work fine, but I haven't tested it enough yet to judge if the design is good enough to develop further.

Future project

Here's an instrument which I'd like to make some day:

• Three string blues slide guitar
• For playing seated
• Sliding nut
• No strap
• Spine: 30 X 12 mm aluminium rectangular beam - freely vibrating
  
• Piezo pickup on aluminium beam
• Sliding pickup under strings- probably an ultra flat one with few primary windings and a current transformer.
• Plunger tuners (this principle)
• Minimalistic ergonomic body - the first version would probably be made from heat-bent acrylic plate

New tuner design

In the previous post, I described my intention of creating a playable testbed for experiments with different pickups. It turned out to be nice to play, so I improved it with a strap horn and the acrylic body from my t-beam bass. As it turned out, it was quite neck heavy. And since I prefer a headless guitar in most circumstances, I began to consider a tuner system down behind the bridge plus removing the headstock.

The design - as many others - uses traditional tuners mounted at the end of the guitar. Most of the existing designs however, has the strings fan out from the bridge and onto the tuners. The tuners have a lot of distance between them in order to allow room for the fingers when tuning. One solution is a design using two rows of three tunes facing each other and sharing the same slot. For the latter, I bought a set of six twelve-string tuners (they have the pegs closer together than six string tuners, saving space).

I built a bracket for mounting them on the end of the testbed guitar. It is soldered together from rectangular brass profiles. The profiles carrying the tuners are at an angle so that there's a (reasonably) straight string pull.

The tuners are made from one side of the twelve string tuners, cut in half - i.e. 2 x 3 tuners. I found out that they had a nice copper coating beneath the crome, so I filed away some of the chrome. I hope, when the steel and copper oxidizes, that they will look more discreet. They seem to work decently, but I imagine that better quality tuners might improve the system somewhat.

The strings can be tuned easily and precisely. Mounting the strings is a bit troublesome, but will probably be easier when I've tried it a couple of times. Unfortunately, my soldering job was insufficient and the top plate broke off. When I re-soldered it (and bolted it too, to be on the safe side), I was too hasty, and the holes for the pegs didn't line up. I had to do a bit of filing, and now the arrangement works, but less smoothly than the first time. I'm not completely satisfied, so I will buy a machine vise for my drill press and make a better bracket. That will give me a chance also to try some better tuners. They could be these due to their good looks (though it might look too _deliberately aged_ for my taste) or these due to their high gear ratio

If they keep working well, I'll cut the headstock off the neck, but for now I am anchoring the ball end of the strings in the existing tuner pegs on the headstock. I plan to play it for some time and make sure that it's a keeper (the overall design, not this particular version). I've got to be certain this works before chopping away.

The developing guitar

I have begun preparing a testbed for my experiments. I want something that's playable. It should be a proper guitar. But it should also be a proper testbed for new pickups, forearm support, strap horn and leg rest.

It's built from a warmoth strat neck and a piece of 20 x 60 mm rectangular steel tube.

For now, it has a tele style six saddle bridge, but that might be replaced by one of my own designs. It also has traditional tuners in the headstock. I'd like it to become headless at some point, perhaps utilizing the bridge and coarse tuners of my SG experiments. But for now, I haven't developed a headless tuning system of sufficient quality. Plus, it's such a fine neck and I'd hate to cut it.

It's a Warmoth strat superwide wenge neck with a pau ferro fretboard and stainless steel frets. I bought the neck because I have very big hands and I'd like to try if a wider neck made better room for my fingertips at the fretboard (it did, but I think it's a bit _too_ wide). I'm not yet skilled (or courageous) enough to attempt building a playable, fretted neck, so I thought it wiser to buy one.

The design of the ultrawide neck with its overhanging fingerboard at the body end makes it fit the steel tube nicely.

The pickup is my own design. It is inspired by the Lace Alumitone and a thread on the guitar electronics forum. More on that and other pickups in a later post. The distance between the strings and the steel tube allows for easy swapping of pickups, as long as they're not too thick (which mine aren't).

I'm planning to make a strap horn, forearm support and leg rest from scrap mahogany. That'll make it a playable testbed, allowing me to try out new pickup designs, exploring their abilities while having fun playing. Other parts, such as bridges and other shapes of forearm support etc, can be easily replaced as well.

The interchangeable wooden body parts are inspired by Spalt Instruments.

Mahogany sides for the T-beam

Almost a year ago I mentioned the mahogany sides that I was going to make for the two string T-beam bass. They're coming along slowly, but they're far enough to be shown here.

The main thing is the added mahogany sides. But another thing I've done is rounding off the corners and edges of the T-beam and tuner plate. It makes it look a bit more friendly and playable without the sharp edges.


The lower bottom of the beam is curved in order to follow the shape of the acrylic body. I plan to make another body from a thicker (5 mm) piece of acrylic. It will look a lot like the current one but it is going to have two thigh rests like the Strandberg guitars, which gives a wider variety of playing positions.

I used a surform rasp, belt sander and sand paper. Plus a table router for the inside cavities for tuners, saddles, etc. On the bottom image, you can see burns and tearoffs from the routing, but luckily they're hidden when the bass is assembled. I also bought a spokeshave, but found it difficult to use. I'm slowly getting better at using the tools, but there's a long way to go before I'm going to be really satisfied with my craftsmanship.

Next steps are routing a channel in each side for the sliding pickup bracket, sanding a bit more, and oiling the wood. I'd like to give the pickup bracket a more elegant shape than it has now, so I might do some cutting and filing here, too. Then there's the acrylic body. Knowing myself and the speed at which I work, the body probably won't be finished this summer.

Copper shield and switch added

I've made a couple of additions to the switching system of my black SG. One of them is a series/parallel switch down by the tone and volume knobs - on the brass disc that leads the copper tubes into the control cavity. I also added a copper shield to cover the holes left by the original knobs and switches. It's still quite fresh and pink, and looks a bit out of place, but I expect that once it has oxidised a little it will turn a more brownish hue and blend in nicely with the rest of the metal.

At present, the shield is only fixed by the nut of the tone and volume pots. I'm still contemplating wheter to use a few screws like on the brass shield or - which would look interesting - a lot of small brass tacks along the edge.

Exposed cabling in copper tubes

The black SG that I used for experiments with coarse and fine tuners has been modified further. I wanted to be able to phase switch the pickups. Plus, I'd had this idea of having the cables run in copper tubes to shield them from noise. The copper tubes should be on the face of the guitar rather than running inside the body. Each switch or knob should be mounted in its own separate hole with copper tubes running to and from it.

Apart from shielding the wires, I thought it'd look good. And not only good, but also logical. I want to be able to see what's happening with all the switching... to know which pickup is going to what swith and from there to which pot. That way, swithcing would be more transparent. You can't see how the wires go to and from a six way selector switch beneath a strat pickguard, and I missed that. The six-way switch is easy to use, but leaves you clueless as to what is hapenning inside the control cavity.

So I made a phase switching system for the black guitar. Each pickup goes to its own On/Off/Counterphase switch on the upper horn, and from there, they both go to the control cavity. Each switch is mounted in a brass disc. If I should keep true to my principle, I'd have to also mount the tone and volume pots like this, but I'll stop here. I expect that on a future guitar, I will fully implement the copper tube and separate switches/pots design. For now, I'll stick with it as it is.

It looks pretty much as I expected it to. I like the... "functional steampunk" look of it, though I use the word with some caution. There's quite a lot of the steampunk design aspects, that I like ...the combination of wood, brass and copper, for instance. Still, I think that steampunk has become too much about old-fashioned costumes and glueing cogs and sprockets on top of things. And then spraying them with copper. I wouldn't add anything just for its ornamental value. It has to have a purpose.

Opinions are welcome, constructive criticism even more so.