That Double Bass I began (quite some time ago) has sat in the corner of my shop, sneeringat me every time I look that way. That has to stop…but the only way to stop it is to finish the project. (sigh…)
One of the things that was holding me back is that my old home-made bending iron simply wasn’t good enough. So, the first step toward completion is to make a new, hotter, smaller diameter bending iron. The old one was heated with a propane torch, but it was quite large, and it took a long time to get it barely hot enough to function. This one will have an electric element for heat, and much smaller diameter, as well as much less mass. I hope it works well. Another maker shared how he made his bending iron, and I am attempting to emulate his example. If that works, I can get moving and complete the bass this fall.
Another Cello
A few years ago, I had salvaged some curly Big Leaf maple from a very large tree that was being removed from my wife’s childhood home. I promised I would build her a cello from the wood, so she would have a treasure from her childhood. So, the wood is fully dry and seasoned, now, having sat out in my shop for several years. It has humidity-cycled through the changing seasons, and should be quite stable, now. A friend (Steve Stevens, now deceased) had given me a cello top set of Red Spruce, so that will go into the mix as well, making it a treasure to both of us.
What I hope to do, is to give special attention to getting good pictures of every step of the construction and finishing of this cello, so as to post a running commentary and tutorial as I work. On every project thus far, I have had a tendency to get engrossed in the work and forget all about pictures. So, I may recruit Ann to take the pictures, so that I can keep rolling.
A Large Viola…or maybe a Viola da Spalla
I haven’t decided just how large, yet…the largest violas I have made in the past have been 16-1/2″ on the body, which is pretty good sized, and already too big for some folks. But I am considering either a 17″ (or larger) viola, or a “Viola da Spalla”, sometimes called a violoncello da spalla, or a small Violoncello piccolo. The Viola da spalla is played off the right shoulder, so that the chin is over the bass lower bout, but not on a chinrest. A strap holds the instrument up under the player’s chin, and the bowing hand reaches up from beneath, to access the strings. Frequently they are made as a five-string cello, and that is how I would approach it. Tuning, then, is in the same range as a cello, but adding one higher string: C, G, D, A, E.
Either way, I realize I am probably building something I will never be able to sell, as there isn’t much market for either instrument. (Ah, well… some things we do out of love.) Anyway, this one is not a very high priority.
Another Violin
The last violin I made received good reviews, but I can see things I could improve, so…I will probably make another one soon. (This lutherie stuff is addictive!)
Coming Soon
I hope to begin at least two of the projects soon, and begin posting photographs.
Thanks for looking.
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Inner curves of corner-blocks, and both end-blocks, first
I learned to shape only the inner curves of the corner blocks, initially, as well as the outer curves of the end blocks, because if I shape both curves on each corner block, then there exists the possibility that, when I clamp the center-bout ribs in place for gluing, the tips of the blocks may deflect outward, instead of holding their respective shapes.
Also, after the c-bout ribs are glued in place, when I shape the outer curves, in preparation for receiving the upper and lower ribs, I shape the ends of the c-bout ribs at the same time, so that they simply continue the curvature of the blocks, to a feather-thin end condition, before gluing the upper and lower ribs in place. Then, when I trim the upper and lower ribs, it is easy to make the glue-lines between the c-bout ribs and the upper and lower ribs completely invisible, matching the corner of the trimmed ribs at the corners of the instrument garland.
So, here is the mold with the blocks shaped as described above:
Ribs are Next
When using figured wood, I have to make a determination as to which angle the figuring will follow on the instrument. I thought I could just copy whatever the Old Master (Guarneri del Gesu) had done, but, as it turns out, he used highly figured wood for the ribs, all right, but the flame (curl) in the maple went directly across the rib at nearly exactly 90 degrees, whereas mine is quite slanted. So, I have to make a decision: Will I have the curl slant “up” (north) from the back side to the front, or the other way– from front to back?
Really, I simply have to make it consistent, on both the treble and bass sides. Some makers have the slant in the C-bouts going the opposite direction from that of the upper and lower bouts. Some, also, have used a single rib across the two lower bouts, and thus had the flame slanting one way on the bass side and the other way on the treble, and then matched the center and upper bout rib curl to the lower bout rib, so that the grain was consistent all the way around, instead of being mirrored between the two sides.
That sounds good: but, in the first place, I haven’t enough rib wood to pull it off correctly; and, in the second place, it can potentially cause problems later on, if the plates shrink (they are made of wood, remember!) and the ribs have to be shortened a little, to match. If there is already a joint at the center, it is relatively easy to simply shorten each side by a millimeter or so, as needed, and re-shape the end-pin hole. But if the bottom wood is all one piece, the repairer will have to cut through that bottom rib, and establish a new center joint; so the two halves will no longer match perfectly, though it will be pretty close.
Anyway: I usually would first thin the ribs to a consistent one millimeter thickness, and then cut them to length, carefully laying them out as to location and orientation, before bending. This time, I consulted with one of my teachers, who assured me that Guarneri ribs were a little thicker. So, since the ribs came to me at 1.3 mm, I will consider that to be the ideal thickness for this particular instrument.
Then I can bend all the ribs, individually, and set them aside ready to be used. In the case of the C-bout ribs, I clamp them into the mold, where they will cool, and stabilize, in exactly the correct shape. Afterward, I used a small brush to slip glue into the joints, and secure the C-bout ribs permanently to the corner blocks.
When the glue holding the C-bout ribs had dried sufficiently, I shaped the outer curves of the corner blocks appropriately: You can see, in the photograph, below, that the center rib-ends have been shaped along with the outer curves of the corner blocks, so that they will cleanly fair into the curves of the upper and lower ribs.
I then immediately installed the upper and lower ribs in their respective places. In this particular case, I chose to install the lower ribs first. After the glue dried for a few hours, I installed the upper ribs.
When the glue holding the upper and lower ribs had dried sufficiently, I trimmed the ends to the correct length, and filed them smooth. The only “end-grain” showing will be the ends of the upper and lower ribs at each of the corners. I try to make them square with the centerlines of the corner blocks, so that it gives the inpression of a “mitered”corner, but with no apparent glue-joint: the joint is exactly along the corner of the squared-off rib end. The first priority is to have the rib end at the right angle, so it will appear to be perpendicular to the plane of the garland. The next is to file them to look “square” with the corner, as I explained above. Finally, some creative scraping of the C-bout rib-ends will usually move the glue joint to be exactly on the corner of the upper or lower rib, and make it essentially invisible. This one is close:
Linings
The only thing left to complete the garland is to install linings on both the front and back sides. The way I have chosen to use my mold (“French” method…ribs flush to one side of the mold) precludes my adding the back linings until after I remove the mold. That is fine: I also intend to leave the mold in place until after I have set the neck, so I have quite a way to go on that step.
Not everyone installs the neck while the corpus is on the mold. I began doing it when building my first cello, and it helped so much with neck-setting that I have continued it ever since. I deliberately allow the heel to “run wild”, in terms of length (or height, depending on how you are looking at it), so that it protrudes past the back of the neck block a little bit. When all my other items (angles, measurements, etc.) are exactly correct, I glue the neck in place, and before installing the back plate, I simply trim the back of the neck-heel flush with the back of the corpus. Then the back plate fits perfectly, and I am not struggling to get that joint tight. But… I am getting ahead of myself…. 🙂
I cut strips of willow to the appropriate dimensions for linings and then plane them smooth; then bend them to fit the curves of the violin, and finally, cut them to the appropriate lengths, and install them. Willow responds very well to both bending and carving, which is why I prefer it for lining material. I can bend all the linings in just a few minutes, and they will all hold their shape until I am ready to use them.
After the corners are all dry and secure, and trimmed, I cut two small mortises in each block, to receive the linings; then cut the linings to exactly the right lengths for a tight fit. The linings serve two purposes: they strengthen the edge of the ribs, which would otherwise be quite fragile; and they triple the gluing surface area bewteen the rib garland and the plates.
When I have all the linings fitted correctly, I remove them one at a time, apply hot hide glue, re-insert the linings, and clamp them in place, using tiny spring clamps. Sometimes one or more areas are more stubborn, and require a heavier clamp. Then I use something with more authority.
So: there is the garland (rib-structure), essentially ready to use! Next time we will level the garland, and use it to trace the shape of the front plate. At some point before attaching the front plate, I will also trim the linings to a triangular cross-section, so that the inner edges taper to a thin transition, and do not add a stress-riser to the ribs. I’m not certain whether it would affect sound, but the Old Masters did it that way, so I will follow their example. The corner blocks also will be trimmed back to be fairly minimal. I will carve away the end-blocks to each be the shape of half an ellipse, but I will leave them fairly robust, for strength.
You can still see traces of ink and glue on the blocks, looking like gaps…that will all go away when I level the garland.
Thanks for looking.
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Progress Report on the 14″ Oliver Viola, and the Violin Modeled after the 1735 “Plowden” Guarneri.
“Life is what actually happens while you are making other plans.”
Well…company came and went, and the week didn’t happen exactly as I wanted it to; There were other things to do, and people to spend time with. My only daughter was here all week, which was nice– she flew in from Switzerland, with about a week’s notice. We went to the beach, Monday, and spent the day infiltrating all the art and clothing stores in Cannon Beach, then had fish and chips and headed home. 🙂
My younger brother dropped in for a surprise visit today, with my young neice. That was a nice visit. While they were here, a neighbor couple showed up, too. We ate and visited, and had a nice evening. Afterward, I helped Ann trim a hedge and haul the branches to the burning pile. All good things.
So! Progress report:
I am trying to keep the two instruments on parallel tracks for completion…hoping to keep them no more than a few hours apart in terms of progress.
Progress in building 14” Guarneri-model Viola and Violin:
(Hand-carved instruments begun on May 25th, 2016)
Cut and install the blocks. (May 25th)
Prepare the ribs, by sanding (using a plywood jig I made to use with my spindle sander). (May 25th )
Bend the ribs, using the bending iron, and install them on the blocks (several steps). (May 26th, 27th)
Prepare, install and shape the front linings. (May 27th, 28th)
Use the sanding board to flatten front of garland. (May 30th)
Prepare the plate stock (book-match and flatten inner side) (Front only—one-piece backs on both fiddles.) (May 30th)
Use the completed garland to establish the shape of the plates. (May 30th)
Cut the front plate exactly to size, including filing and sanding. (Only got the viola cut out. I will cut out the violin tomorrow night if it isn’t too hot when I get home. )
Lay out and cut out scroll and neck. (May 26th)
(Began carving both scrolls using gouges and small finger-planes—spent a good part of May 28th doing that, while waiting for bending irons to heat up, etc. More time as time and strength allow. That maple is tough stuff, and my hands tire quickly anymore.)
Here is the photo-evidence: Handmade in Oregon 🙂
The instrument on the left is the 14″ viola, and is made of Oregon Big Leaf Maple, and Sitka Spruce. The one on the right is the violin, and is made of European Maple and Spruce. Both have blocks and linings of weeping willow.
I ran out of time and energy, so the cutting out of the violin plates will have to wait until later. Once they are cut out, I can begin arching the front plates, and get these things looking more like fiddles.
As you can see, I am trying corners that are a little longer, this time. I may end up shortening them after all, but I left extra in case I wanted them longer. Usually I make pretty short corners.
Vacation is Over– Back to Work!
That’s all I have to show, for today. I go back to work tomorrow. Classes are over for this term, but I still have to prepare certificates, and arrange make-up tests for those who need them.
(For those who don’t know, I teach Welding Supervision classes at Gunderson, Inc. where I have worked for the last nearly 30 years. I began there as a welder, but nowadays I mostly lecture. Print-reading classes, remedial Math classes, Welding Inspection classes, Safety, Metallurgy, etc. It is not as fun as making fiddles, but it is steady. :-))
Thanks for looking,
Chet
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Some makers, especially those making violas da gamba, Lutes, etc., make much more complex purfling weaves. Some of the Celtic designs employ the technique in very sophisticated ways. The point is to make an illusion of 3-D “over and under” weave in the purfling. As far as I know it has zero effect on tone; just appearance.
Installing purfling
When I left off, last post, the purfling groove was nearly complete, but not quite: I finished picking out the last bits of wood in the “fleur de lis” areas, then went all the way around checking for depth and width.
My purfling bending “iron” is an old-fashioned solder-iron affixed to a brass cylinder with various diameters. I don’t know who made it…I got it from my friend Jake Jelley.
Starting with the completed purfling groove, I first cut and bent the center-bout purfling strips, and inserted them into the grooves, making sure the mitered ends were all the way into the corners of the “bee-stings”, as the sharp miter-ends are commonly called.
Then I cut and bent the long upper and lower bout strips, and fitted them carefully into place, jamming them tightly into the miters at the corners, and trimming them to fit exactly at the other ends.
Then I began gluing the long strips in place, so that they would stay put while I installed the short ones. I tipped the center strips up and inserted hide glue in the groove, then pushed them back in place, and forced them to the bottom of the groove, so that the glue was squeezed out all the way along each strip. Then I repeated that procedure on all the upper and lower-bout purfling strips. Afterward, I could begin work on the “fleur-de-lis” designs.
The “Weave”:
You can see that I had to decide, initially, which strip goes “over” and which goes “under”: In reality, of course, they are all at the same level, but, choosing which gets cut off (thus looking as though it goes “under”) and which goes on through an intersection (thus appearing to go “over”) determines which way the “weave” seems to go. Once I pick a direction, I need to pay close attention to see that it continues with the “over and under” look, to make the “weave” illusion appear correctly. I also try to make both ends the same way (starting “left over right”, for instance).
All that is left on the back, now, is the channel, the edgework, and final scraping. We are officially “on the home stretch!”
Thanks for looking.
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I got up at 5:45 AM (usually I get up at 3:45, so this was luxury), had breakfast, watered some fruit trees, checked e-mail, and got to work. I knew the outbuilding shop where my power tools are was going to get hot very rapidly today (99 deg. F predicted, I think), so I did all I could do out there while it was still cool, then worked in the basement shop for the rest of the day.
I took those rough-sawn ribs and thinned them to 1mm all over, using a fixture I made for my oscillating spindle sander (one of the few power tools I use), and cut out the neck block using my small bandsaw. I have a large bandsaw for cutting up large pieces of wood, etc. That is what I used to divide the back block into the two pieces to be joined at the back center seam (next.)
I then cut out the back and front plate pieces, and joined them, book-matched, so that the grain is nearly symmetrical bilaterally, both front and back. It wasn’t easy this time. I don’t know why. I use a small hand-plane to flatten the edges until they fit nearly air-tight– definitely light-tight. I have a larger plane but this wood was so wild it required a very low-angle plane, set very light, or it tears out at all the curly grain.
I glued the two halves of the front plate together using hot hide glue, and, while it was drying, I cut the ribs to the correct widths and lengths for each of the six pieces, planning as best I could to get the grain to line up appropriately at all junctions.
Once the front plate was dry enough to remove the clamps, I glued up the back plate, in the same manner. Some people get a great center-join using a rubbed-joint method. I have done it that way, but I am more comfortable if I add three clamps after I do the rub.
While the back dried, I planed the front plate to get it more or less level across the inner face.
I took the neck blank and laid out all the measurements on it, and began shaping it a little while I was waiting for other things.
About 11:00 AM I decided I was hungry, so I had a salad and some coffee, and took a picture of the work as it stood:
Back to Work!
I drilled 1/8″ pilot-holes in the scroll block for the pegs. When I drill them early like this I can use the drill press and get the holes perpendicular to the center line. My teacher does not do them this way– he says it risks sags in the varnish, and advocates drilling after all varnishing is complete. (He is probably right, but I can never seem to drill the holes correctly by hand, so I will risk the varnish issues.) I was right about working early in the outside shop– it is really getting hot out there now.
I used the small bandsaw to cut the side cheek excess wood off the pegbox, and trued up the heel where it was too long. From here on out the scroll will all be hand-work.
I used the electric bending iron to bend all six ribs, as well as the front linings. I will have to make some more lining stock– this was all I had for the moment. Fortunately they are easy to make. The linings add strength to the edges of those 1mm ribs, which are otherwise extremely fragile. They also triple the gluing surface of the rib edges, so the joint between the ribs and plates are much more secure. I try to get as much done as I can while the iron is hot, and then turn it off; for one thing, it takes about 20 minutes to heat up: but also, if you forget and leave it on, and then forget it is hot, you can get a bad burn. I keep mine at about 400 degrees F.
I installed the C-bout (center) ribs, and glued them in place with hot hide glue, using wine-cork clamping cauls (donated by a friend) for the small-radius upper corners and broom-handle cauls for the lower corners. (This is really going to be a pretty instrument. The wood is gorgeous. I hope it plays well.) The upper and lower surfaces are an even larger radius, so they will be clamped using a section of large wooden closet rod. Sorry I didn’t take photos of these steps. Wasn’t thinking about pictures…I was just working.
More Pictures
As you can see, the ribs sprang back quite a bit after being bent. I should have thought ahead and prepared a block to which to clamp them while they were waiting to be glued in place. I have such a block–I just didn’t expect the springback to be so severe.
As you can see above, after the glue was dry on the center ribs, I worked the final shape on the upper and lower surfaces of the corner blocks to ready them for the upper and lower ribs. Then:
I installed the upper ribs, and, while the glue was drying on those ribs,
I worked some more on the scroll. At this point the simplest way to begin removing excess wood is by cutting from the sides in to very near the layout lines for the scroll volute (the back of the scroll.) I do this by clamping the neck to a work-surface (in this case a lap-board.) and carefully starting the cuts, one at a time, spiraling up the scroll from each side. Usually I can then remove the waste wood with a knife or a flat wood-carving chisel, but the grain in this wood is too wild, so I had to try to follow the cuts around the scroll with the saw, then do the final cutting with sharp gouges and small planes.
Meanwhile, the glue was dry enough that I could remove the clamps from the upper ribs and install the lower ribs. When the lower rib glue was dry, I installed the front linings. These little spring clamps are really handy. I got them on a sale once, at Home Depot, for about 37 cents apiece, if I remember correctly. They are just right for this sort of work, and I bought over 100 of them…cleaned ’em out at Home Depot.
I had been working on the scroll between other tasks, so it is coming along, too, but I am getting pretty tired, so this is about as far as I expect to get tonight. Here are a few more photos:
And that is it for today! Too tired…gonna call it a night. It is 11:45 PM
Thanks for looking.
Chet
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The linings I sawed up yesterday are now bent and ready to install.
While the bending iron was warming up (which takes about 20-30 minutes, especially in cold weather), I used a very small hand plane to smooth the edges of the linings, since some were still a little rough, especially if they had been the outside edge of the strips I cut from that beat-up 4 x 4 I brought home.
Once the iron was hot enough to make water droplets dance on its surface, I dampened each lining strip one at a time, and used a metal bending strap to force the wood against the hot surface of the (aluminum) “bending iron”. These linings are about 4mm thick, so I gave each segment a full 15 seconds to heat up, or 20 in the case of the c-bout linings which were to endure a tighter bend. As I heated one section, forced against the flattest curve of the iron, I counted seconds, then shifted the wood sideways to heat the next section, still maintaining the curve of the first, and so on, until the entire lining strip had the curve I wanted it to have. You can see that I deliberately over-bent them: I do so because it is pretty easy to straighten them out a little, to adjust them to fit tightly against the ribs.
Here is what they look like now:
Tomorrow evening, depending on how tired I am when I get home, (or probably Friday, since I have to go to bed very early Thursday in order to get up at 2:30 AM and go teach a code clinic class before my regular work begins on Friday morning) I will remove the front section of the mold (notice the screws holding it), which will allow room for the linings to be installed. I will cut the little mortises in each side of each block, to receive the ends of the linings, then brush hot hide glue onto each rib and lining, one set at a time, and clamp them in place with little spring clamps. After the front linings are dry, I will repeat the process with the back linings.
Starting to look more encouraging, now.
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Tonight I shaped the upper sides of the upper corner blocks and the lower sides of the lower corner blocks to receive the upper and lower ribs.
Shaping the Blocks
I did some of the shaping on my oscillating spindle-sander–a very handy tool which has paid for itself many times over–and some with an incannel gouge (Curved, but beveled on the inside face, rather than the outer face), finally smoothing with a half-round rasp.
More work for the Bending Iron
I noticed that during the time the bent ribs have been languishing in the unheated shop, they had straightened a little, so I turned on both the bending iron and the glue-pot, and while I waited for them to get hot, I carved some more on the pegbox of the scroll. It is nearing completion, in terms of depth and inside dimensions, but there is a whole lot left to go before it is anywhere near final completion. It takes about 20-30 minutes for the bending iron to get really hot, and that is about right for the gluepot as well.
Installation procedure
I dry-fitted the ribs first, to make sure that once they were glued in place, both ends would fit correctly and the length of the ribs would lie flat along the curve of the mold. Then I loosened the lower end and slathered the hot hide glue on, and clamped the rib into the curve with a clamping caul (a elongated wooden block shaped to force the rib tightly into the curve of the corner block.) Once the corner block end was in place, I glued the upper end to the neck block.
Note to self: warm the wood before gluing!
The shop was awfully cold, and the glue was gelling very rapidly. I hope I achieved a good joint– if not I can correct it tomorrow. I should have heated the joints with my heat gun, before applying the glue, but I wasn’t sure where it was, and didn’t feel like stopping everything to go look for it…so I just worked very quickly. 🙂 We’ll see how it turns out.
My other work: barge-building
Tomorrow, Ann and I will attend a barge launch at Gunderson, LLC, in Portland, where I work. We build large ocean-going barges, and rail freight-cars, there. Here’s a video of an earlier launch, if you have never seen one: http://www.gbrx.com/Videos.php?expandable=2
(I would rather build cellos…) 🙂 When I get home I will try to get the lower ribs installed, and the pegbox completed.
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