Thursday, January 26, 2012

Thomas Mace and I repair John's theorbo


"A dialogue between the author and his lute: The lute complaining sadly of its great wrongs and injuries".

John Edward's theorbo needed attention. Since his New Year's Day program for The Musicians in Ordinary required using an archlute, his theorbo, which had been suffering many "wrongs", could in the interval, be put right. Being in the holiday spirit myself, I thought what fun it would be to invite the venerable Thomas Mace himself to oversee our work and to lend a hand if he thought things weren't right.

By rapping on the soundboard of John's lute it was obvious from the dull response that one or more of the harmonic bars were loose. Thomas was explicit in describing the technique and the tools necessary for mending this annoyance.

 "Firstuntwist your Strings, only so much, as you may have Liberty to take them from the Bridge.... draw those of the first Head all together through your Hand, and twist them about that Head and Pegs: Then take the other four Ranks of Basses, and do the like with them..." 

I have always followed Thomas' advice but gut strings have a mind and memory of their own and they are an unruly mob regardless of how carefully you treat them.


 "Proceed next to the taking off the Lace, and if it be a Parchment, you may be the bolder with it, and never fear the spoiling of it, for you must have a New one put on." The lace on John's theorbo is made of black cloth cut on the bias. I have several yards of the fabric so I won't mind spoiling it.

Thomas continues: "First, have a Dish of Water , and let it close by you upon a Table, and with a Linen rag,...anoint the Lace all over... and then warm all your  Lace over with your Iron, being red hot..."






The photos demonstrate the technique that Mace describes but the tools are a little different. Thomas suggests; "Let your Smith make you a Four-Square Iron, about the length of your Middle Finger, and about three quarters of an Inch Square...". A friend of my daughter's did study to be a smith but was never able to get started in business and is now building custom bicycles. Obviously following Thomas' directions was going to be difficult so I decided to improvise. In the photo (left) I am using the blunt end an old 25 watt soldering iron. "... and then warm all your Lace over with your Iron, being red hot, drawing your Hand slowly and closely, from place to place, till you think the Lace is hot quite through, (but take heed of Burning) and when you have done so, you may take the Lace at one end, and draw it off, so easily as if It had never been Glewed..."  Indeed! The heat from the iron essentially steams the water saturated lace off the edge of the lute.   This was surprising quick and tidy.


The next procedure: separating the belly from the bowl by slipping a small knife into the glue joint between the belly and the top rib is nerve racking to me; fraught with peril. Thomas agrees; "...Attempt the Belly after the same manner, but yet with more Caution..." Among the the list of tools necessary for this procedure Thomas described the knife to be used. " A little working - Knife; such, are most commonly made of pieces of Broken - Good - Blades..." Well, I prefer our kitchen knives for this sort of thing. My favorite for this operation is a three inch Henckels paring knife. It has a marvellously stiff, thin blade that keeps a good edge with a comfortable handle. I just have to be sure to return it to the kitchen when I am finished using it on a lute.

Thomas explains, "Then take your Little Working-Knife, and begin to try to get it between the Belly and the Back, at the Bottom first... And if you have Wetted, and Heated enough, your Knife shall find an easie Entrance..."


I have only built a few lutes with a lace binding rather than a hard wood half binding. But I must say that at this stage the work is going very smoothly compared to my experience with removing bellies from lutes edged with a half binding.  There are several reasons for this, I think. First, there is no finish under the lace so the heat and moisture that is used to remove the lace immediately attacks the glue joint as well. And then too there is little concern for spoiling the finish on the edge of the belly so if the knife does not "find an "easie  Entrance ... Wet and Heat that part again where you are at work, till you perceive it will willingly yield to the gentle force of your Hand and Knife."



Continuing:
"So when that Flat bottom is opened...then put in your Knife again, and when you feel a Barr, then get your  Knife under that Barr, and so gently force it, till you perceive It loose. And so from Barr to Barr..."
Factors such as the strength of the original glue, the height of the bar ends and the closeness of fit will influence the ease or difficulty with which the bars yield their grasp.


Coming to the area of the neck block Thomas suggests that 
"... you must again Wet and Heat and thorowly, and then 
taking the bottom of the Belly (which is loose) in one hand, 
and the Neck of the Lute in the other, you will find 
(with a little forcing) that it will come off very readily... "

I have seen the results of this manoeuvre on lutes both ancient and modern. It is a sad indictment of those with little patience. Thomas continues with a wiser method; " but if need be, you may take a board Meat-knife, and getting it underneath within, help it to part by degrees."  Lute makers will often glue a thin sheet of paper between the neck block and the belly when assembling new lutes. This aids in the removal of the belly if necessary. This is visible in the photo (below).

"And now your Lute is quite undone, and you must get it mended again as well as you can." Thomas explains in detail how to mend cracks of which John's lute has suffered many, but I repaired those long ago and the problem at hand is several loose bars. "Thus having mended all the Cracks, fall to work upon those Barrs you find loose,


which most commonly be at the ends about an Inch or two... " Thomas continues by describing the cleaning off the  old glue, applying new glue, setting it with a hot iron and holding the joint close until the glue cools. Most interesting to me, he describes making home-made clamps from trenchers. "...it will be convenient that you have in readiness two or three pair of little slips of Trenchers, such as Boys make for Snappers, about an Inch broad, and 4,5 or 6inches long. Tye these, two and two together, at one end with a strong Pack-thread; and they will serve to slip over the Barr end, and so hold It and the Belly very close..."




A trencher is a wooden platter, round or square usually roughly made of beech or sycamore. By the 17th century they were being replaced by pewter, earthenware or porcelain by those who could afford them. The image of a collection of trenchers that I used as a model to fabricate my trencher clamp is taken from:



I quickly made one trencher from scrap beech to see how the concept worked. Of course the success of the idea depends on the thickness of the trencher material which I was only able to guess at. I tied one end tightly together with a piece of gut string. In practice, the amount of pressure that the clamp exerted seemed about right for this operation. It held fast and since the material was wood I didn't worry about marring the top of the belly. Furthermore their lightness in comparison to metal clamps is an advantage for many delicate operations. I intend to make several more to have on hand.

Thomas is precise and thorough with his directions for removing the old glue    first by heating the iron "...to such a height, that you may nimbly and lightly touch, and scorch all those Rough Places...", then to "scrape gently ... to the very Wood ... till you see All clear and smooth." He further admonishes: "Take notice,that in cleaning off Glew, and Paper by scorching, it is only to be done in the Inside of Instruments; for it will spoil the Gloss or Varnish of the Outside of any." Thomas continues; "There is One thing more to do...which is to cleane carefully every Barr end, and the whole Round-side-edge, of the Back and Belly...that the New Glew may take fast hold..."

When all of this was done I was ready for the next step. "First bring your Back and Belly together, and see if
 they will fit...Then fear nothing, but boldly proceed to the Uniting, which must be done after This manner."


 I cringed: "Take your Aul, and after you have laid the Belly True in the uppermost Flat (the top of the neck block)...prick a Hole quite through 
the Belly, in the midst of that upper Flat, and joyn Belly and Back together."

 This serves as a method for positioning the upper belly accurately  during final assembly. I don't have an awl so I used a hand pin-vise with a small drill bit.





Now I want to stop and set the stage for the next few steps in this story.  Gluing the back and belly together will necessitate switching back and forth from a sticky glue brush to a hot iron which I thought would best be handled by four hands rather than two. Thomas volunteered to help, and I appreciated his spirit, but I thought John would be more nimble.

 In the photo John is smearing glue on a small piece of paper (I use 90 lb. water-color paper) My glue pot, lower left, consists of a hot plate, sauce pan and a small plastic container of glue  that I clamp to the inside of the pan with a clothes peg. My "iron" is now a  shortened artist's spatula. For heat I use a propane torch that heats the spatula red hot in a few seconds.



"Now to your Glew-Pot, with Back and Belly, and begin with which you please, and anoint all the Edges Carefully round ... and every Barr-end be sure you touch well...bring Both to the Fire, and warm them a little, and clap them quickly together, and with your Aul prick and fasten them together at the Top in the same hole..." Thomas' expertise and thoughtfulness is evident in the following: "...you must be exactly Carefull, that you Clog neither the Back nor Belly, with the least drop of Glew more than is needfull; for all superfluity of Glew, is hurtfull to the Sound of an Instrument."




"Now having in readiness your Great Iron, red hot, heat the edges thorowly all over, and then especially the upper Flat where your aul sticks, till you perceive the Glew is become warm and thin." For this procedure I used my electric iron set on maximum with a scrap of cloth between the iron and the lute.

 "Then begin with the upper Flat, and with your Fingers you may force it close to its old and true place, and then with little pieces of Paper... cover all the upper flat in the Joynts, yet leaving about a Straw-bredth or two betwixt Paper and Paper, so that you may see how the Joynt joyns, and presently scorch on those Papers, on after another, leaning pritty hard upon each one, with the squared end of your broad Iron, which must not be too Hot, for fear of burning the Belly, yet hot enough to scorch the Papers, and the superfluous Glew, into a Crustiness."




At the beginning I was too hesitant and did not heat the iron hot enough. The glue melted but didn't hold. I held my iron in the flame until it glowed red hot. That did the trick. I was careful to apply the iron only on the part of the paper that covered the area where the lace would lie, both top and side. It immediately scorched the paper. Then I quickly, but lightly, followed through by touching the after-length of the paper. The iron had cooled enough to still set the glue but not to risk scorching the glossy or varnished areas.



"Then after this manner proceed Inch by Inch, first on one side, and then on the other...and be sure at every Bar, you thrust it so close as possibly you can, with your Thumb and fingers; and Paper it well all the way with Scorching..."  
















"...and when you have rounded it Thus, lay it by till next day    
 before you cleane off Those Papers, &c."


When I examined our work I was satisfied that the belly and back had joined properly and the glued had crystallized. The scorch marks seemed ominous and I was worried that I had marred the belly or the back. But I had to wait until the next day.





"And to cleane It, only do Thus: Take a dish of Water, and with a Rag bemoisten all the Scorche'd Papers and Glew, often renewing the moisture..."

 I deviated from Thomas' instructions a little and applied a strip of damp cloth to the edge of the belly. After a few minutes I found that; "they will be so soft, that with your Nails lightly runnimg backwards upon It, it will all come off as you will have it." I was pleased to find that all of the scorch marks fell within the area that the lace would cover.








"When This is done, proceed to the putting on of your Lace..." As I mentioned previously, I have a supply of black cloth that I cut on the bias to enable it to curve around the edge of the belly. Furthermore, I fold the cut strip over on itself and iron a crease in it so that it will lie evenly on over the edge.

"...you shall first lay it in Water a while to steep...and to make it Gentle and plyable...(a short steep will soften the cloth but not remove the crease)... Then (sitting down and taking the lute into your Lap)...Anoint about a fingers length or more of the Lace lightly with Glew...and begin your work at which side you please, holding It hard and close with your Thumb and finger at the top, draw it hard down with your other hand..smoothing it gently backwards and forwards with your Thumb and Finger, till you perceive It has fastened...and so proceed till all be Finish'd."


"This being done, lay by your Lute for a Day or Two, that the Glew may harden, and then you may proceed to the Stringing of it."
                                                                      


This was quite a bit of work and we all thought that it turned out well. John was pleased to get his lute back. Thomas enjoyed sharing his passion for the lute with us. And I am happy to have brought you the story.

The text of Thomas Mace's directions for repairing one's lute that I used in this report is available as a download:

http://imslp.org/wiki/Musick's_Monument_(Mace,_Thomas)
Part II -- The civil Part; or the Lute made easy


John Edwards will play his theorbo at The Musicians in Ordinary next performance:

8PM, Feb. 18th 2012 at Heliconian Hall
WHEN TIRCIS MET CHLORIS

The amours of shepherds Tircis, Corydon etc. and nymphs Chloris, Phyllis and others are laid bare in Baroque duets and dialogues from the time of Monteverdi with guest Bud Roach, tenor and Baroque guitarist.





     





Monday, January 9, 2012

My New Workspace

I am nearly finished re-organizing my workspace. The new bench tops are built and boxes of papers, tax records, magazines and lumber are stashed underneath. I still have to mount tool racks on the walls for chisels but I want the walls to remain free of visual obstructions as much as possible. The area to the right of this photo has the metal storage cabinet for flammable finishing supplies and a pair of stacked IKEA cabinets for everything from templates and drawings to speciality cauls and miniature clamps. These cabinets are  purely functional and necessary but they aren't much to look at so I didn't include a photo.

The machine room (below) is essentially set up but I still need to decide where to place tools such as pliers, wrenches and vise-grips.


This photo is taken from the door way between the two rooms. This area was my daughter's drum room while she was still at home. It is separated from the rest of the house with gyprock plasterboard walls which provide fairly good sound proofing. To the right of this photo (below) is my dust collector that is attached to each of my machines.  The collector bags are slightly porous so when this thing gets turned on they inflate rapidly and spew a cloud of fine dust. In order to contain the pollution I have enclosed it in its own tiny room with furnace filters that allow it to breathe. The window allows me to check to see if it is functioning properly. It does a great job of collecting the heavier dust particles and every workshop should have one.



In the fore-gound of this photo is the thickness sander while the jointer is against the wall.

I don't have room for everything and I have two machines that are redundant. I have decided to offer them to any instrument maker, current or future, in the Toronto area, who is willing to haul them away. They are pictured below. One is a 14' Delta bandsaw that is twenty years old. It comes with a 6" riser (not picture) and assorted blades. It is still an adequate machine. The second is a Beaver Rockwell lathe. The swing is 7" with a 36" bed. I "inherited" this machine from guitar builder Jean Larrivee when I worked for him during the 1976-77 season before he moved out West. I turned all of my lute pegs on this machine up until a few years ago. If you are interested in either of these items let me know:

schreiner@sympatico.ca      My regular instrument building posts will return in a few days.


Wednesday, December 21, 2011

Workshop Re-Organization

December has always been a slow month for me. So this year I decided to use the time productively and reorganize my workshop. This needs to be done every so often and I have been putting it off for some time. I have trouble throwing things away; tools that I may need for some obscure project and wood scraps that could come in handy have accumulated and I have run out of room. Many artisans experience this dilemma.



 I work in two rooms. One contains my machinery; bandsaws, jointer, thickness sander, drill-press, lathes, and a dust collector. The other room is my instrument building area. It contains my principal free standing workbench and several long counter-top type wall benches with storage underneath and all of my hand tools. I decided that I could make better use of the space if  I switched the two rooms. The problem is that there is no place to put everything while I am making the switch - except to pile it up.

Once I made some space in my former machine room I was able to move the machinery into its new location. I was able to move the jointer and drill press myself by putting rollers under them and wheeling them into place. But my bandsaw and thickness sander were too heavy and cumbersome so I hired a pair of movers.

 It was humorous. It took these guys ten minutes. I had removed the table from the bandsaw and unbolted it from its base. The largest guy looked at the bandsaw, rocked it gently on its stand gauging its weight and then putting it in a bear hug carried it into the new machine room. The sander was more problematic because it was a tight fit through the doorway. Once the new storage areas are finished I will be able to stash the boxes that are blocking the window and make progress on getting things organized.
Now that I have some space in my new assembly room (the jointer and dust collector were located against the vacant wall) I can patch the walls and paint. The vacant wall has been finished and in a few days I will build a wall bench with underneath storage. Yesterday I took down the tool racks from the wall on the right (the bandsaw was located here) and patched the rough spots. This morning I painted and this afternoon I'll start building the bench against the far wall. My principal bench will be located in the spot occupied by the cluttered table in the foreground. I hope to be finished soon.

 My New Year's Resolution is to have a great time building wonderful lutes and guitars. And to all of you - Best wishes for the Holidays!


The first image is taken from:  http://quod.lib.umich.edu/d/did/
The Encyclopedia of Diderot & d'Alembert Collaborative Translation Project

Sunday, December 11, 2011

Kaiser Theorbo- Making and Fitting the Extension-Continued

In my last post I was ready to shape the back of the extension. I lay out the line representing the slope on both sides of the  extension.




 I remove the bulk of the material with a bandsaw and finish with a rasp and file. The curve across the extension runs to from one end to the other so I use a block plane to rough out this surface. Once I am satisfied I scrape the curved surface with a flexible scraper to even out the contour and then finish with sandpaper wrapped over a contoured block. I then cut a length of veneer a little oversize and get all the glue up stuff ready: rubber mat, foam strip, gluing board, nearly a dozen clamps and some little contoured wedges. Here's what the glue up looks like.




I assemble all of this on the edge and at one end of my bench. I lay a rubber mat under the veneered face of the extension in order to protect it. Then the extension is put on top. I prebend the end of the veneer on the hot iron and secure it with painter's tape. I use fish glue to glue the veneer in place because it has a long set up time. This characteristic allow me to make changes if I don't get the alignment correct the first time -- which happens. It is a complicated procedure and it has to be done correctly. Once the veneer is in place I lay a strip of foam rubber -- the kind that is available from sporting goods stores to put under sleeping bags. The strip is cut roughly to the  dimensions of the extension. Next comes a piece of lumberyard pine that is cupped from improper drying. I have shaped this piece roughly to the size of the extension and it is laid on cup side down.  Then I apply the clamps insuring that all are equally tight. All of this insures that the veneer is firmly in contact with the curved surface of the extension.



At the neck end I insert six or seven contoured wedges that I have made specifically for this theorbo between the foam and pine board. These wedges push the foam against the veneer and insure good gluing contact. I leave this to dry. The excess is then trimmed. Veneer for the edges is applied in the same manner with suitable pieces of foam and strips of wood. But I don't glue the edges until I have completed the joint for the extension. You'll understand why after I describe making the joint.

Before I begin to form the joint between the neck and the extension I make a full size drawing of the string alignment of the theorbo as it is finished to this stage. This  is intended to show the angle of the fretted neck and the bridge and nut positions. From this I can lay out the line of the first diapason. In this case it is the eighth string. Since I don't want any of the diapasons to hang off the edge of the theorbo head I position the extension so that all of the diapasons fit within the width of the theorbo head that is 65mm wide.

Next I mark a long straight line on the edge of my workbench. This is the layout  line for insuring that the extension is aligned correctly. Then I position the lute upside down  and clamp it to the bench in such a way that the bridge hole for the eighth string and the point where it passes at the end of the fingerboard are correctly aligned to the line on the bench.




In the photo you can see the reference line drawn on a strip of masking tape applied to the bench. The theorbo is firmly clamped to the bench in the alignment that I described. At the far end of the extension I arranged a riser that elevates the extension the proper height. I align the extension left or right along the top surface of the riser to achieve the position that I want for the placement of the first diapason. The height of the riser represents the height of the theorbo head plus the height of the nut. Theorbo extensions bow up under string tension. The only effort I make  to counter-act this tendency is to build in an adjustment factor. I align the extension vertically so that the diapasons will sit on the fingerboard nut before they are tuned to pitch. Once at pitch for a few days I find it necessary to lower the theorbo head nut. I start with a nut height of 25-27mm that is reduced to around 20mm by the time the theorbo is ready for delivery.

Now I can lay out the saw lines on the neck for the joint. This procedure is a combination of experience and guess work. I know how wide I want the extension to be at this point when it is finished (78mm) so I mark this slightly narrow to allow for cleaning up the sawed surface. The minimum gluing surface that I like, front to back, is 35-37mm. If it is a large theorbo like this one I will finish with a surface that is 40mm front to rear. This is because the distance from the nut to the first fret is large enough to allow a comfortable space for the left hand thumb to sit between the end of the extension and the first fret.

 Here's the roughed out joint and the rough fit.

     

The closer that I can come to laying out the joint correctly the less effort it will be to finish the joint, but there is always the danger of making the joint area larger than first intended so I am conservative when laying it out. I have also made the extension over wide. The excess will be trimmed off later. I finish the joint with files and purpose built contoured sanding blocks. When I think I have it right I remove the lute from bench and check the alignment. I have a simple method for holding the two parts together. I attach two strings to the bridge in the first and eighth bridge holes and then to pegs on each side of the extension. When tension is applied to the strings the extension will be drawn into the joint. Two spring clamps on each side of the neck will stabilize the joint vertically. I equalize the tension on each side by using the same diameter of string and 'tuning' them as I draw the joint together.

Once I am satisfied with the fit I trim the edges of the extension to fit inside the width of the joint allowing for the thickness of the edge veneer that I can now glue on (above photo). This will cover the peg holes but they can be punched out from inside the pegbox slot and re-drilled.

I use a template for laying out the theorbo head but depending on the size of the theorbo I will make the head a little larger or smaller to fit the over-all appearance and balance of the instrument by re-drawing it free-hand. I have traced around the template on a carefully prepared, square edged, block of poplar. I  drill the peg holes and cut the nut and string slots all while the block is square. Then I begin to contour the shape with a single band saw cut on the top surface and others on each side. The photo shows the head completed to this stage. Further contouring is done around the front and bottom front of the head with gouges and files. The head is then test fitted to the extension and glued when finished. I stain the natural colored poplar black to match the black veneer of the extension. After a final test fit of everything I glue the extension in the same manner as I described previously.


The next two photos are of historical theorbo heads. The profile view is of the Railich theorbo head in Bruseels. The other view is of the Alban theorbo head in Nuremberg.

The last photo is from one of my instruments.



This finishes my posts on the Kaiser theorbo. I have omitted several steps in its construction or have not elaborated as much as I might have. I am starting another Kaiser at the beginning of the year. I plan on covering elements of its construction that I missed this time as well as discussing its design features.

There are several other topics that I will relate. I started a Lacote guitar but put it aside while I finished the theorbo and awaited the delivery of a set of tuning machines from Italy. Those are scheduled to arrive in January so I will begin my post on the Lacote  construction soon. John Edwards and I repaired loose bars in his Kaiser theorbo following the advice of Thomas Mace using his treatise from 1676. I'll post that story. I am about to finish a Voboam guitar and although I started it before I began this blog and started documenting everything, I do have photos from various stages of its construction and plan to post those. During this last week, and the coming one as well, I have completely dismantled my workshop and am reorganizing it.

All photos are by the author.

Monday, December 5, 2011

Kaiser Theorbo- Making and Fitting the Extension


This is the extension of a Railich theorbo that I built last year. I chose these photos because the white edging makes the extension shows up well. It is veneered front and back with ebony and on the sides or 'cheeks' with walnut. It is long -- it measures 840mm between the fingerboard nut and the nut on the theorbo head.


At the joint to the neck the extension is 78m wide tapering to 30mm at the head end.



The thickness under the fingerboard nut is 22mm tapering to 18mm at the end. The theorbo head itself is another 30mm high without the nut. The top or face of the extension is flat while the back is arched from side to side. The cheeks are angled in from bottom to top.




All of this work removes wood which reduces weight. It also promotes an elegant appearance. You can see the pronounced curvature on the back of this Railich theorbo extension (MIM Brussels). This extension is unveneered solid wood that is stained/painted black.

Below are several photos of historical theorbo extensions. One is traditionally elegant while the other has its own beauty.


Matteo Sellas 1640, Musee de la musique, Paris. The curvature across the extension and the subtle slope in the line of the cheek is a style that I try to emulate. The weight of the ebony and ivory inlay is burdensome to the player. I can't image playing through a long rehearsal with this lute.





The photo on the right is of the Sebastian Schelle 1728,
German National Museum, Nuremberg.  The neck is veneered with ebony but the extension is stained black.  The finish has rubbed off in the area of contact with the player's thumb creating a beautiful patina.
The stain on necks such as these appear to have some 'body' or substance to them. I have the feeling that the finish is a mixture of pigment, oil and a little resin.  The theorbo head of the same instrument, which is a later addition, has a completely different look (below) that is probably pigment with just a little oil.




I use different styles of theorbo extensions depending on the model of theorbo.  German theorbos have a distinctive style and I make a close copy for those. Italian theorbos have a style that changes only in the details and I have developed several models. You can see the difference in the treatment in the area of the extension joint between the German and Italian instruments in two of the previous photos.




The extension for the Kaiser is a typical Italian design.  I always use a core wood of yellow poplar either painted or veneered. For this client I veneered all sides with black dyed pear. The theorbo head is poplar as well, stained black. Other times I cut my own veneer using ebony, walnut or, like on my Tecchler archlute, bloodwood. I start by preparing a poplar wood blank cut a little oversize in length and width but tapered to the correct thickness -- allowing for the veneer. I layout the peg holes and drill them. Then I prepare the veneer for the top surface and glue that on. Since the surface is flat there is no special setup. Then I rout out the cavity for the strings using a template and a small router (laminate trimer) with a flush mounted bearing.

The template is screwed in place. One screw hole will disappear under the neck joint and the other, upper left, is screwed into a scrap of wood temporarily glued to the side of the extension. I can clean up the cavity and cut the distinctive characteristics now or wait until I finish the head. Below are two photos; the Railich pegbox to the left and then the Schelle.










These two photos bring to mind a consideration that I haven't mentioned.  Clearly one theorbo is single strung throughout while the other is strung in courses on the fingerboard with single diapasons. There are few surviving single strung theorbos. Most of the theorbos that are built today are of models that  survive with double strung fingerboard courses and single diapasons. Few modern theorboists, however, want this arrangement and ask for single strung instruments regardless of the model. The Kaiser theorbo is double strung on 'board', as I say, with single diapasons, but I build it with single strings.

All photographs by the author.

Next time I'll shape the rear of the extension, glue on the veneer, make the head, figure out the alignment of the extension, cut the joint and finally glue it together.