Tuesday, November 29, 2011

Marx Unverdorben 16th Century Lute - Report on My Examination

This is a 16th century lute by Marx Unverdorben in the instrument collection of Harvard University. I became fascinated with him years ago when I saw an article in the Lute Society of America Journal that included one of his lutes. To me, he is somewhat mysterious . Little is recorded about his life and although there are nine surviving lutes by him few modern makers build models. I made two trips to Harvard to study this lute and I have just posted the result of my research on my website's project page. http://www.schreinerlutes.com/projects.html

Also you can see a story and detailed photos of a model of this lute that I recently finished on my website. http://www.schreinerlutes.com/PicPage4.html

My next post will be about constructing the extension for the Kaiser theorbo.

Wednesday, November 16, 2011

The Kaiser Theorbo - fingerboard and its points

The elegance and simplicity of the points at the end of the fingerboard belie the difficulty in constructing them. I always have to be very careful when designing and laying them out on the soundboard.  Good looking points enhance the appearance of the soundboard and poor ones are a distraction. These are the points that I cut for my Kaiser. They are not exact copies of the original. The length of the soundboard tongue and the proportional width of the points are accurate but the curve of the points is a little flatter in my version. I don't have a photo of the original but you can see the original by visiting the museum site. I'll explain how to navigate the site at the end of this post.

I'm sorry that the image isn't more distinct. In the photo I have fitted the bass side point and scored the outline of the second point. I begin by preparing a piece of ebony that is the thickness of the soundboard and the width that I want. It should be several centimeters over length. I cut and finish the point to a smooth contour. I under cut slightly the two edges that fit against the soundboard. This negates the width of the knife blade while making the cut. I tack glue or attach with double sided tape the point in the exact location on the soundboard. Then I score lightly along the two edges. After removing the point the score lines can be deepened until the soundboard is cut through. When the waste is removed the point should fit snuggly. If the fingerboard is curved the points should be curved as well. I glue them in place with thin glue and secure with elastic tape and a couple of wooden wedges as I demonstrated in my last post.

This example is from the Tieffenbrucker lute, E. 980.2.321 in Paris. I don't find the narrow, short point attractive although they are easier to make. Note that the points are wider than the fingerboard at the tied fret. This instrument was converted from an Italian theorbo with a long extension to a shorter German style swan neck lute. The neck was narrowed to accommodate a different style of playing.

CURVED FINGERBOARDS. I arch the fingerboards of all of my lutes that are 10 courses or more. Even though the original model may be flat. My clients appreciate the comfort this feature affords. I accomplish this by curving the neck core itself rather than adding a curved layer of wood to the top of the neck material. Arching the neck core does necessitate cutting into the top edge of the side ribs but the effect is that the strings lie closer to the plane of the top of the lute. On a lute with a single neck lute the edge strings will actually lie below the plane at the nut. This lessens the upward pull on the neck.
For wider fingerboards I always use multiple pieces of ebony for the following reasons. It is difficult and expensive to buy wider boards and I like to minimize the amount of sawing. The stuff is filthy. So I buy guitar fingerboards and cut those to the desired thickness. Then I glue the pieces to the curved neck core separately, starting with the center piece. The following photo shows my system for clamping them.

I cut pieces of used belt sander material in lengths that can be wrapped around the neck. I put a spring clamp on the free end and just at the edge of the piece of fingerboard that I am gluing and then a second clamp on the other side. I repeat this process the length of the fingerboard for each of the separate pieces.

You can visit the Musee de la musique website at: http://mediatheque.cite-musique.fr/masc/  Once on the museum page click on the caption of the right side of the page; INSTRUMENTS DE MUSIQUE, OEUVRES D'ART. On the next page click on INSTRUMENTS ET OEUVRES D'ART. This opens the catalogue page. Type E. 24 as the inventory number or enter Kaiser as the facture.  Once on this page you may enter any instrument you like  in the search and the museum's entire holdings are displayed.

In the next post I'll build the theorbo extension. 

Friday, November 11, 2011

Kaiser Theorbo - Fitting and Gluing the Bridge and Belly

Today I am going to describe the techniques that I use for fitting the belly to the bowl, gluing the bridge on the belly and then finally, the belly to the bowl.

You will remember that in a previous post I paid a lot of attention  to fitting the temporary belly. This accuracy comes in handy again when I fit the top to the bowl. Before I glued the bars in place I drew the outline of the bowl on the underside of the belly. This line is clearly visible in the photo and it is the reference for fitting the belly to the bowl. After I have shaped the bars (in my previous post) I trim the bar ends so they terminate inside the reference line an amount equal to the thickness of the edge rib. If I have done the trimming correctly the belly will slide into place on the bowl with a slight amount of friction. The reference line will be visible just beyond the edge of the bowl. 

I won't describe the making of the bridge now. I will be starting another Kaiser this winter and I will describe those techniques at that time.

In this photo I have laid out the bridge position with painter's tape, a square and a center line drawn on the same tape. I found that it was difficult to balance clamps on the narrow top of the bridge so I make an insert that fits on the rear platform of the bridge. The top surface of the insert is level with the top of the bridge so the clamps have a wider surface to sit on.

The metal clamps are resting on the block part of the bridge while I use cam clamps with rubber pads on the bridge wings. I use just enough pressure to insure good contact between surfaces. Under the bridge area I fit wood cauls between the various bars. This assembly can then sit on the edge of my bench and the clamps can span the distance from the bridge top to under side of the bench top.

Once the bridge is glued I place the belly on the lute and using a length of sewing thread tied to the bridge like the first string I make sure that it aligns accurately with the edge of the fingerboard and that the height of the string at the neck joint is what I anticipated. Now I can glue the belly. I mark the location of each bar so when I start to apply the tape I secure those areas first. I apply a coat of thin hot hide glue to the edge of the bowl, the ends of the bars and the underside edge of the belly. Then, working quickly, I apply the tape over the entire edge of the lute, pulling the tape taunt and carefully pressing it in place.
Securely gluing the tongue area of the belly was a problem so I developed this technique that has worked well for me. I wrap elastic tape tightly over the upper part of the belly and under and around the neck. Then I insert opposing wooden wedges. This action presses down on the belly resulting in  good gluing contact.

John Edwards, theorboist and co-founder of Musicians in Ordinary dropped off his 1998 Kaiser theorbo this afternoon. It has a problem with loose braces. Sue, my wife, looking over my shoulder as I wrote this post commented on the jarring nature of the green tape. I agree, but it does the job. On the other hand, I am reminded of the technique described by Thomas Mace in Musik's Monument published in 1676 for repairing his lute belly that involves just what I have done here and what needs to be done to John's lute but using seventeenth century techniques and materials. Since I have to repair John's lute why not follow Mace's advice and really be a 17th century lute maker. It will take me about two weeks to get to this. I'll report on it here.

Monday, November 7, 2011

Harmonic Barring for the Kaiser Theorbo

Many lutes that I examine are intact so unless a drawing has been made of the the interior, perhaps during a restoration, I must find other means to discover what the barring is like. Such was the case when I examined the Kaiser theorbo in Paris. No drawing was available but I knew from visiting the lute on the museum's website that there were several long, wide cracks in the belly that were wide enough to see several bar locations. When I had the theorbo in front of me I could clearly determine the location of all of the major bars. Since I had prepared paper probes that I could slip through the cracks I was able to measure their size.

Although I do not have a photo of the inside of the Kaiser soundboard I do have this photo of a large triple rose lute belly by Magno Tieffenbrucker that is in the Metropolitan Museum of Art. This lute and the Kaiser are similar in length, width and position of the triple rose so the layout of the bars is similar.

But the position of the bars is only one of my concerns. Even if I copy the bar locations of original lute - which I don't necessarily do - I am concerned about the quality of wood that I use. This, I think, is one of the most important elements in instrument construction. I cut up blemished soundboards from my stock which works fine for smaller lutes and guitars but some of my larger theorbos need bars that are thicker than the normal thickness of stock belly wood. To solve this dilemma I buy cello tops. This allows me to cut whatever size of bar I need. An additional advantage is that from instrument to instrument I am assured of uniformity in density and strength of my bar wood.

The photo on the right shows some of the bars already glued in place and others still under the clamps. I start by gluing the small  rose bars. One of them is visible just to the right of the clamps in the center of the belly. The side that is visible through the rose is stained black. I usually place four of these bars under each rose. Three larger bars that span the width of the belly are placed through the centers of the pair of large roses, one bar through the center of the small rose and a third bar across the area in between. Note that I clamp the bars in five locations across their width. My bellies are thinnest in the center at each bar location along the belly's length and it is necessary to press each bar firmly into this slight depression. I glue the bars in groups that are the same height so I can minimize the number of clamps.  I adjust the height of individual bars in the next step.

Although I vary the basic bar layout from one Kaiser to the next very little I will alter their size. This is not because one soundboard may be stiffer than another but because each of my clients attack the theorbo a little differently. One may like a little stiffer instrument, another one a more compliant instrument. I accommodate these differences by adjusting the bar sizes. In this photo I am rounding the top of the two harmonic bars. Once this is done for all of the bars I will cut the slope at their ends. Historical lutes show different treatments of the bar ends in height and angle.

This photo shows the ends of bars from the Epp theorbo (formerly attributed to Hoss) in the collection of Harvard University. They are left high but are cut at an angle that prevents the full height of the bar from contacting the inside of the rib. This frees the edge and results in a very resonate but less powerful instrument. I prefer to balance the resonate / power by leaving the bar ends from 5  to 7 mm high and in full contact with the inside of the rib. This is an example of one of the methods that I use to personalize my instruments for my clients' playing style.

In my next post I will fit the top to the bowl, make the bridge, glue it on the belly, tune the J bar and the small finger bars that support the bridge area and then glue the belly to the bowl.

All photographs by the author.

Wednesday, November 2, 2011

Tools and Techniques for Carving Lute Roses

The collection of items in the photo is all of the tools that I needed to cut the theorbo triple rose. At the top is a bottle of mucilage that I use to glue the rose pattern into the belly wood. Mucilage is a glue usually associated with children's crafts. Since I cut the pattern from the front I need to remove the remaining paper of the pattern so I want a glue that is easy to remove. Which it is. Next is a well used block of paraffin for lubricating the knives. The circle cutter is used for scoring the borders of the roses as I described in previous posts. Of the two knives that I used the first is an X-acto with a #11 blade. The second is a small violin maker's knife. Two sizes of small gouges came in handy for scoring the outline of the tighter curves of the organic elements of the design. I do use small chisels (not shown) for some roses but they were not useful for this design. I do use a small magnifying glass. I do all of my carving on a self healing mat.

I want to demonstrate several features of my carving technique so I made an enlargement of the rose pattern - one that would show up better in a photo - and glued it to a scrape piece of soundboard spruce. Using the violin maker's knife I score all of the lines on the pattern, firmly and precisely as possible.  In the photo at the left I am using the violin maker's knife because it has a thicker blade that is easier to control. If I  deviate from the pattern I balance the mistake by maintaining the proper width when I cut the opposing line.  Although I have reduced the soundboard thickness to 1.1 - 1.2 mm in the rose area it usually isn't possible to cut completely through the belly in one stroke. The elements of the design, especially the ones that align across the grain of the wood , are weak and easily broken. To prevent this I cut a "relief" to the line. That is what I am doing in the photo. You can see a bit of the paper pattern and wood curl up. This is accomplished by holding the knife at a 30-40 degrees angle while making a cut parallel to the original perpendicular one. The adjacent area has already been "relieved". 

Here I am making my final cuts. I am using the X-acto #11 because it has a thinner blade and is less likely to push the wood apart, fracturing the fragile rose pieces. I seldom use the #11 for the initial cuts because the blades are too flexible and are harder to control.

The direction of these cuts is important. Although it is not clearly visible, the grain of the soundboard runs from side to side in the photo. All of the cuts run across the grain at varying angles. To prevent the end of the exposed grain from grabbing the knife and throwing it off course I cut "down" grain or with the "nap". You can feel this effect by making similar cuts diagonally in each direction on a piece of spruce. A key to understanding the problem is to note that the direction of the cuts on opposite sides of the center element between the two marked areas are opposite. It is a good idea not to remove a waste area until the adjacent areas are completely cut. Making the final cut on one side of an element that is not supported on the opposite side can lead to breakage. Note: Lubricate your knife frequently with paraffin.

The border of each rose has a ring of diagonal blocks that are chip carved on their corners. I lay out the spacing for these with a template that I made specially for each rose.

 It is made with a protractor on a piece of poster stock. The circle of the rose border is marked off in five degree intervals and an area corresponding to the border is cut out. This template is positioned exactly over the rose border and taped in place. Now a knife cut can be made diagonally from one line to the next. The result is 72 equally spaced diagonal blocks. Two opposing edges of each block are now chipped off to create the final effect.

 I have finished the theorbo so obviously it is quicker to build them than to blog about them. My next post will explain my system for barring the soundboard.

 My theorbo's new home is the Music Department of Grand Valley State University in Michigan.