11 February 2011

Building a Guitar with a little help from Andreas Krueger

It has been some years ago that I build my first guitar. I did it not by my own but  attended a workshop "The master guitar design and construction" which was directed by Andreas Krüger a well-known builder of classical guitars in Bielefeld / Germany.


After playing on several Yamaha guitars and a handmade master guitar from Jose López Bellido I still had the feeling, that I was somewhat missing. . I wanted to play a guitar made by myself to get a feeling what makes a guitar sound. But I was afraid to do it alone, for I had not tackled such a big project until now. So when a friend called me and told me that there was a workshop I was really magnetized. My decision to sacrifice money to realize my dream of a home-built guitar was near. The application to the workshop was accompanied with many phone calls ahead, circling again and again to questioning my own abilities, the seriousness of the workshop and the equivalent of the course. Andreas Krüger, or just the Meister, as we called, sounded in the preliminary talks not only confident, but could, as it turned out later, keep all the promises.
The accommodation was fantastic, and the 'intensive' workshop had actually left no time for other leisure activities. The projected 100 hours for the construction had to be pressed into two weeks.


Each of the three participants had his own working environment with all necessary tools. For coarse or time-consuming work performance machines were in a separate room. These were  explained and demonstrated as needed, so that we could use them during the workshop as a matter of course.

This point reflected the methodological approach of our Meister. If deployment was necessary, for example using a  belt sander, the device was demonstrated in a practical manner. In further use, we were asked to be taken for granted for independent use of machine. For wood work and the related tools he was using the same approach. In order for this 'confidence-building measures’ to have the desired effect, problem solving in the first few days could be carried out with relatively high tolerances. The final precision was then called at a later date. This procedural approach dropped some of the tension among the participants, because you still had 2 mm clearance and thus safety in the wood.


Nevertheless, there was constantly the fear that a ‘precious’ work done could be destroy irrevocably by a careless slip-up.  This encouraged us to the necessary caution in using the tools and was only towards the end of the workshop degraded by increasing security.

But if the chisel slipped once we got from our Meister another  lesson on the topic of guitar repair. Basically it was the great respect for the wood. Wood is not a cheap purchasable  merchandise. It should be considered in each case as a unique product of nature.  Accordingly, the wood stock of this workshop was not layed out for a production 'Just in Time'. It was treated as a guarded treasure.

My Label

Apart from the work process that was exhausting for all concerned, the general mood remained relaxed. Our Meister, who had to dived his attention by three, knew to keep his calm and resolve emerging tensions with concentration. The topic ‘guitar’ was almost always the center of discussions. And if you ever wanted to escape, you could retire to a small sales area, get one of the guitars and start to play.

Each of the coming luthiers  found his own rhythm of work and time synchronization was not essential. This also had the advantage that there was no rush hour on the machines.

Back plate Rosewood

The Construction 

When every participant designed and planed his guitar,  the concept by Andreas Krüger proved to be very flexible.

The following specifications were given:
  • Spanish concert guitar with a predetermined shape
  • Mensur 63 / 64 or 65 cm
  • Spanish body / neck joint
  • Spanish head / neck joint
For critical parts of the guitar preliminary decisions were taken:
  • Cedro headstock
  • Cedro neckstock
  • Ebony neckstock
  • Ebony fingerboard
  • Brazilian Rosewood bridge
  • Spruce bracing
  • Bone nut and saddle
Thus we could select the wood for the soundboard, the ribs, the back plate etc. according our wishes to satisfy our musical and visual needs. The result of this Workshop showed up three different guitars:
  • Cedar / Rosewood
  • Spruce / Rosewood
  • Spruce / Maple
The tone woods which we used were well seasoned and of very good quality. Concerning the embellishments (shoulder, sound hole purfling etc.) we could draw from the rich stock of the Meister.  Special wishes for inlay work in Jugendstil were satisfied and  decorate the upper part of the body and the headstock of the spruce/maple guitar.

The construction of the guitar followed essentially the spanish method. The bracing of the soundboard was based on the aural desires of the builder and the physical requirements (symmetric or asymmetric bracing, Bouchet-bar, sound hole reinforcement, etc.). The Plantilla that outlined the individuell corpus of the giving guitar was appropatly supported by a solera. This vault  was part of every workplace.

The ribs were according to the Spanish method trued up into the slots of the heel block. The head stock  / neck conjunction was glued accordingly. The back-plate was not strutted outside the Solera. Three arched main struts were fitted and laminated  into the frame. This permitted a very accurate determination of the   surface curvature of the back plate.


After detailed explanations of the possible tone woods, wood structures and criteria for identifying good tone woods it checked the soundboards in stock for strength and stiffness.  Subsequently we started cutting and gluing the neck (Cedro, two boards and spacing with a strip of  Ebony. This was followed by the fixing  the bent head and neck block.
The joining and gluing of the base plate and the soundboard caught then a major part of our attention. All were happy, when the view by the gap of the two boards in the back light produced no more glow and one could begin with the gluing.

The good results of the first steps encouraged us to deal with the planning of the head shape, the veneer and the layout of the soundhole rosette. The shape of the head was designed and cut out  a half-mask. After this step the selection of the veneer wood and the splinters took place, so that at this time the aesthetics was specified to a large extent. After the ditches had been milled and circumvented around the sound hole, the inserts had to be fit in, glued and straightened accordingly.

In the meantime after the glueing of the cover veneers the head was marked out and sawn out with the help of the template and bored the holes for the machine heads. This no short process was of course, but had by fine work to be supplemented again and again.

In the next work procedure the neck block was brought slowly in form, so that the rough form of the neck stick became recognizable.

After the soundboard on the front side was finished, the back plate had to be planed off. The soundboard was shaped on different (between 1,7 and 2.3 mm) strengths. After cutting the sound hole, which was set aside as memento, we began strutting the back of the soundboard. The spruce borders were prepared accordingly and planed and glued in a special tightener for the cover, which lay in the concavity of the Solera. In this way the cover accepted also the necessary curvature.

Subsequently, the bracing was formed still in such a way that she contributes an optimum with as little a mass as possible to necessary stability. The neck of the guitar, the conclusion block and the curves of the Stöckels were formed after similar criteria. This carving produced for me some sort of stress situation so that the safe hand of the Meister  was demanded. Finally the neck approached of the strength for its future appearance. Thus the downward gradient in the neck was roughly pre-worked and appropriate material with a special plane was removed.

The soundboard received the last struts and the transverse bracings at the sound hole, before it disappeared in the baking oven. Before the gluing of the trims the moisture content of wood was brought on approx. 10%. 

Subsequently, the before straightened trims were fit in and glued in the solera. The soundboard was joint with the neck. The connection of the ribs with the soundboard was made by small "Leimklötzchen" and a portion bone glue.

So slowly the guitar took form. At the other edge of the trims toward back plane glue borders were attached. Here it was to be particularly made certain that the intended curvature of the back plate ran evenly.

A final touch to the back plates, the ribs fit in, the sound board coated with glue and consolidated with an enormous amount of clips and fastening clamps. After this ' Hedgehog' had rested over night, the ' box' was closed…

The joy on the next morning, when the half-finished guitar came from the Solera, was not to be hidden, and milling the edges at back plate and sound plate brought further security that the ' box' was on the best way to a genuine guitar. The splinters for the edge inserts were still preformed but glued at a later time by tape. Still important working steps were necessary  in order to prepare the surfaces finely.

The next larger project was the fretboard, which had to be modeld. The hardness of ebony made things difficult for us. The adjustment of the fretboard, measuring the fret distances proved to be not so difficult. Only as came to the sawing of the narrow slots for the frets, one grumbled somewhat louder. Positioning and straightening the frets is not done in a half hour, but swallowed up by the necessary filing  operations for several hours.

It was as usual an orgy with sandpaper, rasp, file, sandpaper and steel wool. Little things like der Stöckel conclusion and breaking all the edges had to be done even before the neck profile was also planed to its final shape and height and ground. It's a nice feeling when you can adjust the neck on his own hands.

Thus only the bridge made in the meantime remained to be positioned on the soundboard.

Yes, and to the conclusion the strings could be finally drawn up, and it passed the miracle, for which we waited 14 days with tension: The whole did not look like a guitar, but she sounded also like a real guitar.

The master guitar

Even though I'm no master, I can be confidently proud of what I have created with the help of the Meister. Externally it is a guitar that provided with decent ornaments. But also under beauty criteria  it does not have to hide herself in a guitar case. The design features fulfill all characteristics of an elevated guitar and the sound, for me the most important and most subjective matter, was filed by another renowned luthier in the higher category.

This is an updated artikel I wrote several years ago for the german magazine "Gitarre Aktuell", but I thought that the subject is still up to date. Andreas has announced new courses. You can find the old article (in german) on my other website here .

A just got a hint from simonm in the classical guitar forum: Lots of pictures from another course by Andreas Krueger. Thanks!

Stay tuned for the other articles about building classical guitars.