Lute and Historical Guitar Building with Michael Schreiner: Buchenberg Theorbo in Yew

When I reported on my last Buchenberg theorbo (June 20, 2018) there were two clients who were interested in buying it. I finally finished a second one.

This one has several important differences. The fretted string length is 93 centimeters, rather than 89 centimeters while the diapasons remain 170 centimeters. The bowl is constructed with 29 ribs of yew rather than bird's eye maple.

Several years ago my stock of European yew was getting low and I only had short pieces suitable for Voboam guitar backs. I found a source for western yew in British Columbia that is sold as bow staves. They are long and narrow, usually only 2 x 2 inches. Some of them are suitable for large theorbos. They are sold online with a video presentation of each stave. I started buying the most promising ones several years ago and storing them in my shop. A few months ago I felt they dry enough to start using.

I used the same construction techniques to assemble the bowl as the one I described in my post mentioned above.

This is the string trough of the large Buchenberg theorbo No. 1570, that is conserved in the Musical instrument Museum, Brussels. See my post from August 7, 2018 for a full description of my examination of this instrument.

I modeled this design on my Buchenberg from 2018 but after complaints concerning the difficult angle of the first four strings over the nut I reverted to using a string trough with a narrow treble side cheek

I painted the string trough with a traditional oil paint. It has an egg shell finish.

The ebony line up the center of the extension is not only an aesthetic feature but also a necessary addition. The English walnut that I am using has a light curl that shows best on the quarter which is cut from the edge of the board. The board is two inches thick so it was necessary to use parallel pieces that I book matched. The ebony edge lines and the center continue to the theorbo head where they complete the simple design feature with mitered corner joins.

The face of the theorbo heads are often fitted with contrasting lines. I used walnut and ebony with broader walnut pieces.

The rear of the extension displays the same aesthetic as the front.

A second set of ebony edge lines begin after an interruption, wrap around the head and join a cross-over line just behind the extension nut.

In my post A Special Kaiser Theorbo (December 20, 2019) I described a technique for bending tight curves by soaking the small strips of wood in white vinegar. I tried this with ebony strips without success.

I reverted to the proven technique of steaming the wood and then bending on a hot iron. After several more broken pieces I finally got two perfect ones. The problem lies in the poor quality of black ebony.

Bending tight curves with ebony strips is notoriously difficult. Much of the ebony that is available these days is cut from trees with irregular grain or is cut off the axis of the trunk. The strength of any wood is dependent on the wood fibers running parallel. Any deviation results in a weakness that is exposed in the wood's inability to resist fracturing when stressed.

I turn my pegs from well-aged Castelo boxwood. They are stained black with a spirit soluble stain and then lightly lacquered. I turn them without using templates. There are some inconsistencies in the shape and size. This is intentional. I believe this is one of the many features where subtle variations reflect the instrument's personality.

The core of the neck is quartered Sitka spruce. It is veneered with strips of California Claro walnut which has a broad diagonal curl. I alternate the direction of the strips to create a random effect. The edges of he neck are veneered with ebony in order to protect against fret damage.

I always enjoy looking at the soundboard of this Buchenberg theorbo. The contour is graceful yet full of energy and the placement of the triple rose and bridge are so harmonious you can almost hear the instrument-without plucking a string.

The sound board is fine grain Swiss alpine spruce.

I often use variations of Leonardo's knots not only for its universality but also because I can cut it entirely with miniature chisels and gouges. I do my best work with these tools.

You can see all of my posts on rose carving by entering "rose carving" in Search This Blog located below the Blog Archive.

The bridge follows an often used 17th century design.

I used European plum and copied the dimensions of the large Buchenberg theorbo conserved in the MIM Brussels (see next photo).

The value of this design is that it lends itself to subtle adjustments, both when it is made and after it is glued to the lute's soundboard. I believe the design of the finials offers the same properties, effecting mass and acoustic distribution, as the cut-outs in the bridges seen on the violin family of instruments.