Maple is a lot tougher to carve than Spruce is, and European Maple is tougher than the domestic maples. But it has to be done, so, we get going on it. I chose to carve the back plate for the Titian model violin, first.
Beginning Planing, using a toothed plane.
Later, as I came nearer to having the plate correctly shaped, I switched to a smooth, curved-sole finger plane. I have two main toothed planes, to which I have affixed wooden handles, so as to distribute the force across my palm, instead of concentrating it on my fingers and thumb. I don’t need the handles as much, using the smooth planes, because I am usually making shallower cuts.
Checking relative curvature with a straight bar.
The arching is still pretty rough, but it is beginning to take shape.
After the shape is nearly complete, I switch to scrapers, and try to accurately match my arching templates. Finally, I use a flexible scraper with which to smooth all transitions, and leave a finished surface.
Arching is nearly finished.
Completed Titian back plate with Plowden plate just begun. (Using a smaller toothed plane.)
It is interesting to see the different wood colors. I bought both from the same source, but they are certainly not from the same tree. That is OK. Both are good European Maple, and will work very well.
Both plates nearly complete–the Plowden plate still needs work.
I was getting too tired to go further this evening. My hands were beginning to hurt, so it was time to call it a day. After I finish the scraping and shaping of the Plowden back plate, it will be time to begin the interior arching (graduation). Also, I ordered a different pair of neck blocks, because I realized that the pair of neck blocks I had were actually Viola neck blocks, and I hated to waste them. So, when the new blocks arrive, I will also lay out and begin carving the two necks and scrolls.
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I used scrapers, very gently, in tight corners, and very worn 400-grit abrasive paper, more aggressively, on the easily accessible areas, to remove all the loose, or overly thick areas of the gypsum pore-filler from yesterday. It took longer than I expected, but this was the result:
Front, ready for sealer.
Side view.
Back, ready for sealer.
You can see that the grain is somewhat obscured, and the color is quite light. I am wondering whether I did not succeed in rubbing the gypsum into the wood, as thoroughly as usual. Usually, the color has been nearly chalk-white. I can see the gypsum in the wood, though, so I am going to press on with the sealer coat.
Sealer Coat
This time, the sealer consisted of ordinary rosin in a solution of “pure spirits of gum turpentine”. I probably should have made it a little thinner. It was about like light syrup; so, afterward, I dipped the brush in plain turpentine, and went back over the instrument to help the stuff penetrate a little better. The turpentine will all evaporate over the next few days (I hope), leaving only the rosin, solidifying in the pores of the wood. It is always impressive to see just how completely the gypsum disappears, under the sealer.
The back plate, with the sealer coat applied.
Front plate and side, with the sealer coat applied.
Different light angle shows the curl in a more attractive mode.
Now What?
Until that sealer dries completely, I will have to find other things to do. But it is hanging in a warm room, so it should dry rapidly.
After that, It will be varnish coat after varnish coat, until it it is all done. Then the final set-up can occur.
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When I installed the back plate, the heel had been trimmed flush with the back of the garland, but the upper surface of the heel was still quite irregular, and the upper end of the button was ridiculously oversized. The excess wood made it easy for me to install a clamp, and get the back plate glued on securely. So…when I removed all the clamps, this is what it looked like:
Back plate installed; button and heel not yet trimmed.
Next, I will trim the button and heel, then add purfling, then scrape. These are the tools I will use.
This is roughly the shape the button will be, but a little more refined, I hope.
Side view of the heel and the button. The closeness of the camera warps the picture a little.
Installing the Purfling
The next thing was to scribe in the purfling slot. I used the purfling marker to scribe the double line exactly 4mm from the outer perimeter of the plate, except the corners, where I used a sharp pencil to sketch the “bee-stings” in by hand. Then I incised the lines all the way around, just barely deepening the lines, so that they are more visible, and a little easier to follow with the blade of my small knife.
Purfling slot lines lightly incised.
Then I slice in pass after pass, trying to get the lines deep enough for the purfling I will install. I usually find that, especially on the hard maple, I have to cut the slot in two layers: the first gets about half the depth I want, and the second finishes the slot. Here is the slot at half-depth:
It looks good, but it is not deep enough.
Purfling slot ready for purfling.
Back purfling installed…glue still wet. 🙂
And the Front!
Back to Work!
As most of you know, I had undergone hernia surgery, just after Christmas, and had a 6″ x 8″ polypropylene mesh patch installed in my abdomen. I have been convalescing, and just this week, have finally been feeling better. So…I just received word that I will return to my work at Gunderson, Inc., tomorrow at 6AM. I think I had better call it a day, and try to get some sleep. 3:30AM comes at the same time, every morning, whether I am ready or not. I will get home sometime after 4PM, I expect. Maybe I can jump back in where I left off. 🙂
Tomorrow evening, then, I hope to complete the purfling channel and the outer edgework of both the front and back plates, and begin the final scraping in preparation for varnishing. Any little glitch, regardless of how tiny, will be very visible under the varnish. So this part has to be done with great care.
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When I last posted, I had just begun the graduations of the front plate. I got tired, and had to stop. It has been frustrating, finding how little I can accomplish, currently, before feeling exhausted. I hope I regain the strength and stamina I once had. Here is what the plate looked like yesterday morning:
Rough graduation nearing completion.
The plate was still far too thick, but was at least looking encouraging…so I plunged in and brought the whole plate to approximately 3.5 millimeters thickness all over. This is the first time I have tried this graduation scheme. In the past I have been very particular to have one thickness in the center area, another, slightly thinner, above and below that area, and thinnest of all, out in the flanks. But, I am informed that that is not such a good plan. So…here we go!
The pencil is only there to cast a shadow: otherwise it is difficult to see the curvature of the completed plate.
Completing the F-Holes:
Once the graduation is complete, I need to finish cutting out the f-holes: I begin with a special tool called an “f-hole drill.” For years I worked without one of these little gems, but my children finally decided I ought to have one, and bought it for me. 🙂 The use of the tool is self-explanatory, and there are a wide variety of bit-diameters, for violins and violas. (I later bought another, larger one, for cello f-holes.)
F-hole drill.
After drilling the four f-hole “eyes,” I began cutting out the rest of the f-hole outlines, using a knife and a small saw.
F-holes still need to be cleaned up…but there they are!
Completing the Purfling Channel
Now it is time to start cleaning up the purfling channel, and fairing-in the curves, up into the arching. I began with a sharp pencil, and drew an “edge-crest” line, approximately 40% of the distance in from the plate edge, toward the purfling. Then I used a sharp gouge to remove a shallow channel across the purfling, which ended at the edge-crest. Then I used scrapers to smooth the transition between the edge of that channel and the arching curves.
Edge-crest line, and gouge, beginning channel.
Beginning the Channel
Channel is cut: now scraping can begin.
Treble-side scraping is nearly complete.
The treble side channel is essentially complete. When I have the whole channel completed, I will flip the plate over and install the bass-bar. All along the way, I will continue to fine-tune the f-holes, until they are satisfactory. Right now they are quite rough, but my hands are tired, and I am fearful of making errors due to fatigue. So…they can wait. 🙂
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As I work by myself, I frequently fail to take pictures. I did take a few, though. (If you are impatient, you can scroll down and peek at them.)
F-holes Cut Out
I used a special tool to begin the cutting out progress: It is called an “f-hole drill”, but all it really amounts to is a specialized twin-blade hole-cutter. My children bought it for me, one year, and it has been a wonderful tool. In the first place, obviously, it is a time saver, but the biggest difference is that I can now make the upper and lower eyes of my f-holes perfectly round, to begin with, and work any special shaping in, starting from the already round holes.
I remove the waste wood from the uprights of my f-holes with a small sharp knife—many makers use a saw, and I have done so as well, but I eventually reverted to the knife. Just personal preference, I suppose.
Bass Bar
Once the f-holes are cut out and close to perfect (always allowing for later nit-picking), I install the bass bar. The bass bar is a gently-arched brace supporting the bass-side foot of the bridge. Guitars have a whole collection of similar bracing, supporting what amounts to a nearly flat (and very thin) plate. The violin family instruments depend primarily upon the compound curves of the arching to supply strength, and only need the one brace to support the bass-side bridge-foot. The other side of the bridge is supported by the soundpost, which, while it is not directly under the treble-side bridge-foot, it is very close to it, and is in a location on the treble side matching the lateral position of the bass-bar on the bass side.
I lay out the position of the bass-bar, and then use a compass to transfer the shape of the inside of the front plate to the bass-bar blank. Then I use a knife to remove most of the waste-wood, and begin checking the results against the inside curve of the front plate. When the fit is getting close to correct…close enough that it is becoming difficult to see what needs to change…I apply a strip of paper-gauze adhesive tape (available in pharmacies) to the inside of the plate, covering the bass-bar position, and I rub blue chalk into the tape. I happen to use a product sold as “sidewalk chalk;” they are big sticks of chalk, and supposedly are easy to wash off of sidewalks. But they work well for me, and the blue is high-enough contrast that I can see it easily.
I press the nearly correctly-shaped bass-bar into the chalked tape, and check to see where the chalk transferred. I cut, plane or scrape just the chalked places from the bass-bar, repeating until, finally, when I press the bar into the tape, the whole thing comes up lightly coated with chalk. Then I remove the tape, clean off any remaining chalk from both pieces of wood, and install the bass-bar, using hot hide glue and clamps. I have a specialized set of wooden clamps made for this task.
When the bass bar glue is completely dry, I remove the clamps and trim the bar to the desired shape. I make my bars a little higher than most luthiers do, in the center, but tapering to about 5-6mm high for the last few centimeters of both ends. (I will take some pictures after I remove the inside mold, so you can see the final shape.)
Edge Preparation
It is much easier to do the inside edge-work if I do it before I install the plate on the garland. So, I use a tiny finger-plane, along with round and flat files, to round the inner edge of the plate, all the way around the perimeter. I may have to do a little correction later, but I want it as close to perfect as is possible, before gluing the plate to the garland.
Installing the Front Plate
I line up the plate on the garland as accurately as I can, matching the center-line of the plate to the centerline of the garland, and then use spool-clamps to hold it in place. I was originally taught to use tiny pins to assure good placement, but eventually discontinued the practice. We know for a fact that the old masters did this, as we can see the remnants of those wooden pins in their violins, still today. Perhaps I will eventually resume using pins. For now, I do not.
Once I have the plate perfectly aligned and securely clamped, using a very thin palette knife, I slip hot hide-glue into the joint between plate and garland, and then add more spool clamps to draw the joint closed. This is a very “stress-free” way to glue plates in place. I used to experience near-panic every time I installed a plate, racing to clamp the joint before the glue gelled, but now it is a very easy and relaxed task.
Purfling
As you may remember, I have not yet installed the purfling. I wait until the plate is on the garland before purfling nowadays, because the purfling “locks-in” the location of the plate edge, and I have had problems in the past with the rib garland changing shape a little, between my tracing the plate and trying to install it. so, after gluing the plate to the garland, the first step is to double check my over-hangs, to see that they are all pretty close to the same. If I need to change them, I do so: I am free to adjust the shape of the plate to match the garland again. When the overhangs are all acceptable, I begin purfling.
Purfling is fairly simple-sounding:
mark the groove location
cut the groove,
fit the purfling,
glue the purfling,
mark the edge crest, and
cut the channel.
It sounds easy, but I still find it a hard job to do perfectly. I want my miters perfect, my bee-stings clean and sharp, and all my borders parallel. This is my 30th instrument from scratch, and I am still finding it to be challenging. Guess I am a slow learner. 🙂
Cutting the Channel
Before I begin cutting the channel I use a compass to mark a line all the way around the instrument, 1.6 mm in from the outer edge. Then, using a sharp, curved gouge, I cut my channel to that edge crest line, trying to cut the whole channel to intersect the surface of the purfling and that pencil line.
Fairing in the Channel to the Arching
Once I have the purfling completed and the channel cut, I still have to fair-in the surface of the rest of the plate to match the curvature of the channel. I do not want there to be any sudden changes; humps and hollows catch the eye of the person looking, and call into question the skill of the maker. (Besides, I think they are ugly….) I use a very sharp finger-plane to begin shaping the surface of the plate and approximating the final curves I want. Finally I use sharp scrapers to bring the curvature of the whole plate to its final shape. I use a low-angle light to cast shadows from any humps or hollows, so that I can spot them and scrape them away. At this point, the scraper has to be sharp, and I have to use a gentle touch. The changes I am making are frequently much thinner than a piece of paper.
Outer Edgework
After the whole plate is the shape I want, the last task is to shape the outer edge. I begin by using a tiny finger-plane to take the outer corners down at a 45 degree angle, then use half-round files to shape the edge all the way around, bringing the curve of the outer edge up to just intersect the edge-crest line I established earlier. I get it as smooth and even as I can, using a file, but I know when I stain the wood with coffee, it will raise the grain terribly along these edges, so I will eventually re-smooth all of them, using abrasive paper of some sort. In this particular case, I did the outer edgework after setting the neck. No special reason…that is just what I did.
Neck Set
I measure carefully, and cut the tapered mortise using a razor-saw, then use a sharp chisel to remove the waste wood of the mortise. If I do the job correctly, it works very well. I check the sides and bottom to the mortise to see that they are flat and straight, then begin attempting to fit the neck. I have already joined the fingerboard to the neck and have shaped the heel where it will join the neck-block. So, from this point forward, all the shaping and adjustment will be done to the mortise, not the neck. When I am satisfied that the fit is correct, the neck will have to be centered. straight with the centerline of the front plate, straight with the centerline of the end block (not twisted at all), and at the correct angle to place the end of the fingerboard at the right height. Also, of course, the neck has to be set so that the distance from the nut to the edge of the front plate is correct. I check and re-check, until everything works correctly. Since I set the neck before installing the back plate, I want the heel of the neck to protrude past the back end of the neck-block. I will plane it flush after the glue is dry.
Here is the completed mortise, cut for the neck. The outer edgework has yet to be completed. You can see the edge-crest marks.
The mortise is complete, and I am ready to set the neck.
There is the dry-fit neck set. Notice the overhang of the heel of the neck beyond the neck-block. That will be planed off after the glue is dry.
So there is the dry-fit assembly. It is starting to look like a viola!
When every measurement is correct simultneously, and the fit is tight, I remove the neck one last time and slather hot hide glue into the neck mortise. Immediately I jam the neck into place, and quickly check all those measurements again. Bingo! They are all correct, and I can relax while the glue dries! Once the glue is dry, I plane off the neck heel overhang, flush with the neck-block.
The glue is dry, and the neck-heel overhang has been planed flush with the neck block. I am ready to remove the mold.
In this picture, I have filed the outer edge curvature already, and, though you can’t see it in this photo, I have also completed the graduations on the back plate, and have filed its inner edges, so it is ready to install. But; before I can do that, I have to remove the mold and add the back linings.
Ready to remove the mold.
Dreaming of the next step!
I am getting tired, though, and have some other things that need doing, so the viola will have to wait until another day to move any further toward completion.
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When I left off, last time, I was too tired to continue carving, so I took a break and completed other responsibilities for a few days. Saturday, I came back and spent some time carving and scraping:
Final outer carving complete–beginning scraping.
As you can see, the basic shape is complete. Scraping will be the method of moving wood from here on, on the outside… the inside is still a flat, rough plank. But I continued scraping for a while on the outside before beginning the inside.
Back plate with scrapers: I used the “shmoo”-shaped scraper to clean around the inner bout edges and the others to establish the final shape of the outer curves.
Once the plate is essentially the exact shape I want it, (checking with low-angle lights, etc.) I move to finer scrapers– sharpened at 90 degrees, and used gently, flexing the blade to match the curvature of the plate.
Final scraping: this is not to say that more scraping will not be done later, but that will be after the purfling is completed. This is about as far as I will go until then.
Beginning the inside arching and graduation
Now I can flip the plate over and begin carving out the inside of the back. Here is the cradle without the plate. Notice that the plywood cutout matches the shape of the plate fairly closely, while the thick pine board simply supports the plate while I am carving. The plywood is what holds it still, laterally. The spring clamps prevent the plate from flipping out of the cradle.
Working cradle for violins and five-string fiddles. The hollow shape allows the cradle to be used on both sides of the plate. The full-thickness cutout allows chips to drop through and not obstruct the work.
The back plate has already been marked for inside arching. I will have to monitor thickness constantly, but here it is, ready to carve:
Back plate ready for carving. Notice the lines mapping out the general shape to be “excavated.”
And, the “fun” begins again. This Koa wood is by far the most difficult wood I have ever used on a back…but it has to be done, so, chip by gouged-out chip, here we go:
Beginning the inside arching, using a gouge again.
I will post again when I am ready to install purfling.
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Remove the mold and clean up the interior of the corpus.
In my case, since the mold is collapsible and comes apart in several pieces, it is pretty convenient to get the mold out. I use a small electric screwdriver to remove eight drywall screws, and back off twelve more, and the thing just comes right out…no fuss. The twelve that were just backed out are the ones securing the corner blocks and neck and end blocks in the mold. So, here is the corpus, fresh off the mold, with all the blocks still square and rough, and the linings only roughly trimmed, not scraped.
Cello interior immediately after removing the mold. All the blocks are still rough and square. Linings still need final scraping.This is the end block. You can see the rounded part that I shaped before installing the front plate, so that I would not risk damaging the front plate while shaping it. The rest of the block was out of reach in the mold. Now it is time to shape all the blocks.Here’s what the corner blocks and linings looked like. The linings had been trimmed with a knife, but not scraped.
So– the next hour or so was spent chiseling, planing and scraping all those blocks to their final shape, and scraping the linings as smooth as I could get them. Here is what it looked like afterward:
I tend to make my neck and end blocks a little oversize. I have seen blocks split and break, because they were too small…it seems an easy way to insure against that sort of thing. All the blocks are now the size and shape I want them, and scraped smooth.
Install the Back Plate
So, the next step is to get the back plate in place. I aligned it carefully, checking all the margins to see that the overhang was fairly even all around, then clamped it in place, dry, using spool clamps. After I was satisfied that the overhangs were correct AND the elevation of the fingerboard was correct (an easy thing to mess up, as the corpus is quite floppy at this point), then I clamped everything solidly, and began removing a few clamps at a time, and inserting hot hide glue, using a palette knife. I washed off the excess glue with hot water, and re-tightened all the clamps.
Here the cello is in all its spool clamps, with one bar clamp to secure the button to the heel of the neck.
The cello back is fully installed, with hot hide glue and spool clamps. The bar clamp secures the back button to the neck heel.The house was pretty cold this morning, so I decided that the cello would dry faster in a warm room. Close to the woodstove (but not too close) is the best place I could find.
Final edge-work, scraping, preparation for varnish
After the glue was thoroughly dry, I removed all the clamps and began trimming edges, and perfecting the scroll and heel. The heel was almost a half inch high (which I expected…we leave extra, so that the heel and button are trimmed and shaped together, and match perfectly when we are done.) The scroll was still quite rough. I spent the rest of the day and late into the evening, scraping and planing, and trying to get the cello ready for finishing. Finally ran out of steam about nine PM, but it is nearly complete. Here is what it looks like tonight:
Cello in the white, from the front. A little more edge-work to do, tomorrow morning, and I can begin the finish work.And there is that one-piece back…it has come a long way since that big slab we started with, hasn’t it? I still have some final smoothing of edges, etc. to do, then it is time for varnish.
Actually, I typically use a very weak water-base stain first, which will make the spruce a tan color, instead of cream-colored. Then I will sand it lightly with fine micromesh, seal it, and start applying varnish. (On the home-stretch, now!)
For those wondering about the pegs, saddle, nut, etc.; I wait until the varnish is complete before adding those fittings.
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The Inside carving (Graduation)on the one-piece Cello back is complete.
Planes and scrapers ruled the day
Here is what it looks like now:
The scrap of lining material is only there to cast a shadow so you can see the curves.Same thing again, but with a bigger stick. 🙂
Again, you can’t see it very well, but I also rounded the edges, beginning the edge-work that is so important to the finished product. I do the inner edge first, as it is hard to access once the plate is installed. I began with a tiny plane, and cut a narrow bevel all the way around the edge, at a 45 degree angle. Then I used a file and a scraper to round it into what is essentially a quarter-circle curve.
This plate is ready for installation.
I will try to close the corpus this week, and then scramble to complete the neck and scroll.
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Today I used low-angle light to reveal all the humps and hollows, and used scrapers to bring all of them to a smooth continuum of curving wood.
“Flat F-holes”
Once I had the front plate fairly smooth, I laid out the f-holes, and incised them deeply. My reason for doing this is that every single instrument I have made, the arching proved to need correction, as revealed when I laid out the f-holes. Invariably the arching was too “puffy” around the lower ends of the f-holes, so I had to re-carve that area. Finally it occurred to me that if I cut the lines in, they would remain visible as I carved, and I would not have to lay them out over again. That turned out to work pretty well, so now I routinely assume I will have to correct the arching, and I incise the f-holes, then view the plate from the side: what I am aiming for is that the general shape of the f-hole will seem to lie in a plane parallel to that of the ribs when the instrument is assembled, rather than describing a lazy “S” from the side.
Here is an example from an unfinished viola, from several years ago:
Flat f-hole
It is not something “exact”, but more of a general impression. One way or another, it allows me to see when my arching is not right, and correct it.
So, here is the top plate with the f-holes incised. I will finish cutting them out after the inside carving (graduation) is nearly complete.
Cello Front plate with f-holes incised
Here’s an end-view…doesn’t show much:
End view of Cello Front Plate
And a sort-of “3/4” side-view…trying to show the curves:
3/4 view of Cello Front plate
Here’s a close-up of the c-bout with the f-hole incision (I used a special f-hole cutting tool to incise the circular parts):
C-bout with incised f-hole
Annnd the back plate: (still may be a bit puffy in spots…I will work on it more later. Right now my hands are hurting from all the scraping) That’s all for today! I’m worn out.
Side view one-piece Cello Back plateEnd view of one-piece cello back plate
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