Friday, November 20, 2015

Building a Stauffer Terz Guitar- Part 2

In my last post I focused on constructing the adjustable neck and the corresponding V slot.  Now it is time to describe assembling the body of the guitar.

Since I had cut the V slot before I glued the front block onto the side ribs it was essential the everything remained properly aligned. With the side ribs clamped securely in the mold I then clamped the mold to the edge of my bench with the axis positioned on one of the lines on the mat. Then I glued the front and rear blocks in place.

The back slopes gently toward the waist and then plunges by nearly 15mm to the neck joint. The height of the side ribs are contoured from 77mm at the tail to 70.5mm at the waist and then to 56mm at the neck joint.

 This creates difficulty in bending the interior linings for the back because they must conform to both the outline of the guitar and the sloping profile of the sides as well as fitting snuggly against the inside of the ribs. When the profile is less drastic the linings can be bent and twisted into the proper shape. But here that is not possible. I solve the problem by making my lining material extra deep, bending it to the contour and clamping it to the ribs, letting the extra width overhang. Scribing a line, as shown, denotes the correct profile. A second line scribed parallel to the first and then removing the excess makes the linings uniform in depth.  

Once the linings are cleaned up I complete the frame by shaping and fitting the struts for the top and back. These all follow the size, shape  and placement given on the museum's drawing - with one exception. I added a smaller strut, thinner and lower,  in a position behind the bridge.  I like to assemble the backs and tops in this manner. The ends of the struts fit perfectly into notches in the linings, and as a result, the frame is perfectly stable and remains so when the top and back are glued in place. The three back struts are arched as much as 4mm for the lower bout and nearly 3mm for the upper.

The two lower struts on the top are arched 3mm while the two above the rose are flat. These values are my choices.  I also include a thin maple bridge plate that conforms to the arch of the top. The museum's drawing has no information about arching, nor is a bridge plate part of the original guitar.

I describe my technique for gluing the back and top onto the struts and frame in  "older posts" from 1/20/13, 9/19/11 and 9/10/11.

The original Stauffer soundboard is thin. The area from the bridge through the sound hole and up to near the front block is 2.1 - 2.2mm. Other areas are 1.9 - 1.7mm. I used the same sort of gradation but I started at 2.4mm.

J.G.Stauffer MIM 4152, Berlin

 The museum plans do not include details of the purfling or the design of the bridge. I photographed the guitar but only in its location in a free-standing display case. The photo is of little value because of poor light and reflections.

N.G. Ries, private owner

I do have a Nicolaus Georg Ries guitar circa 1840 in my shop.  I consulted it for the design and details of the bridge, purfling, peghead and neck contour.

The Ries purfling design is similar to that found on many of Stauffer's instruments so I chose a variation of that for my terz.

Because the waist is so tight I didn't trust the strength of the my masking tape to hold the multiple strips in place at the waist. Also, I chose   not to glue on the thicker hardwood outer piece  at the same time as the others. I substituted a plastic strip and glued everything in the normal way. A special purpose caul with a large cam clamp that spanned the waist secured a tight fit. Hide glue doesn't stick to plastic so the next day I peeled the strip off and glued  on the final ebony strip.

The Ries bridge (see previous photo) is a delicate design that was often used by the Viennese builders. The original is made with a hardwood painted black. I photographed the Ries bridge, re-sized it to the dimensions I needed, printed it and from that made a simple template. I chose a piece of European plum, drilled the bridge pin holes and cut the saddle fret slot.

Here's the finished piece ready to be blackened.
Viennese bridges are usually very low. This one is 5mm high, tapering to less than 2mm at the ends. The rear slopes to about 2.5mm.

Next time, I'll post a photo album of my finished guitar with further descriptions and explanations.

All photos by the author.

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