Posts Tagged ‘graduations’

More Progress: Plates and Scroll.

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More Progress: Plates and Scroll.

Completing the Back Plate

I continued planing away wood from the inside of the back plate until it was very nearly correct, then switched to scrapers, and completed the inside surface, so that it looks to be a smooth continuum of curves, transitioning without a ripple. The  plate will require no further attention until I am ready to install it. Unlike the front plate, I intend to install the purfling later, after I am completely sure how the garland will respond to having the mold removed (sometimes they can move, and change shape a little.)

Back Plate Graduation complete.

Back Plate Graduation complete.

 

Scroll Progress

I also continued working on the scroll. My hands were getting pretty tired, so I took a break from that. It is still quite rough, but, here’s how it looked at break time:

scroll beginning

Long way to go.

 

scroll progress

On the right path, but “miles to go before I sleep.”

 

Bass Bar Fitting

To fit a bass bar, I begin with a completed front plate, and lay out the position of the bass bar, so that the distance from the center to the bar, level with upper and lower bouts at maximum width, is 1/7th the full distance from centerline to the edge at those respective points. Usually, that means that the lower point will be about 15mm from the centerline and the upper one about 12mm (as it is in this case.) I lay out a line through those two points, and observe where it is, nearest to the bass-side f-hole. If it is too close, I “fudge” it away, a bit, trying not to change the angle. (The bass bar has to clear the f-hole.) Then I mark the two ends, 40mm away from the ends of the plate, and that is the place to fit the bass bar: the “footprint”, so to speak.

Bass bar position laid out.

Bass bar position laid out.

 

I use chalk to fit my bass-bars. I have never had a good enough eye, and a sure enough knife-hand to accurately fit a bass-bar without the use of chalk, though I have known master makers who regularly did so…perfectly. (Sorry… I’m not good enough for that.) On the other hand, I have had some nasty experiences with the residue of blue chalk mingling with the yellowish hide glue when installing a bass bar: it left a very ugly green stain…and it never completely came out. So…what to do? In the first place, I switched to pink chalk. If a little chalk is left, the glue will simply make it look a bit orange. (No problem.) But, I really don’t want chalk residue at all.

A friend showed me the paper “gauze” tape available in pharmacies. It is thin enough to completely conform to the surface of the plate, and  produce a good fit, and, it is slightly translucent, so I can see my layout lines through the tape, and keep the chalk on just the path of the bass bar. I first use a compass to mark the general shape of the bottom of the bass bar, and then trim it with a knife and a small plane. That gets me “in the ball-park,” so to speak. After that, it is chalk-fitting time.

The front plate is made of European spruce, but I chose Sitka spruce for the bass bar. There is quite a contrast in color between relatively fresh European spruce, and well-aged Sitka spruce. It actually made it a little difficult to see the pink chalk against the dark wood. But it worked.

Bass bar blank, knife-trimmed after tracing the shape with a compass.

Bass bar blank, knife-trimmed after tracing the shape with a compass.

 

paper gauze tape

This is the paper gauze tape I use for chalk-fitting.

 

Paper gauze tape and pink chalk

Paper gauze tape and pink chalk, ready to begin chalk-fitting.

 

Layout lines visible through the tape.

Layout lines visible through the tape.

 

Layout lines traced over on the tape, to make them more visible.

Layout lines traced over on the tape, in pencil, to make them even more visible.

 

Chalk on tape.

Chalk on tape.

 

Chalk transferred to bass bar

Chalk transferred to bass bar

 

The idea, in any chalk-fitting procedure, is to press the fitted part (being fitted) into the chalked surface to which it is being fit, then trim away only the portions where the chalk transferred. So, in the case of the bass bar, I need to press it into the chalked top plate, and then check the bottom of the bass bar blank, to see where to cut. I trim off the obvious spots, and try again. Ideally, every time I try, I will get a broader transfer of chalk. When the whole area gets a light dusting of chalk at one time, the fit is as close to perfect as I can get it. I remove the tape, wipe off any chalk residue, slather the hot hide glue onto the bottom of the bass bar, and clamp it home. On a good day, it takes me a half-hour. On a bad day? Don’t ask… 🙂  This time wasn’t bad, though.

Chalk-fitting complete; Dry-clamped to check fit.

Chalk-fitting complete; Dry-clamped to check the fit.

 

Tight fit

The fit is good!

 

Glued and clamped

Glued and clamped. 

More Scroll Progress

While the glue was drying on the bass bar, I went back to work on the scroll. It was looking verrry rough when I had to take a break, so it is nice to see it progressing better, now. There is still a lot to do. I have to excavate the pegbox, and cut the fluting in the volute. But this is as far as I am going tonight. I am glad to call it a night, and let my hands rest.

More scroll progress

More scroll progress: there is still a long way to go, but it is looking better.

 

Scroll partly complete.

Final status for tonight. Looking a lot better, and more encouraging to see.

 

I have other things to do tomorrow, so I may or may not get to work on the violin. At the very least, I expect I will be able to trim the bass bar to the shape I want it, but beyond that, I don’t know.

 

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Violin Progress

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Violin Progress

The Front Plate is Complete, except for the Bass Bar

This morning I got back to work on the scraping, and completed the outside of the front plate. The interior is also essentially complete, but still lacks the bass bar, so there is still that to do. I spent some time cleaning up the f-holes, and I am somewhat satisfied with them, but undoubtedly will do some tinkering later, just because I always do, and am never quite satisfied with them.

Front plate

Front plate

 

Back Plate Graduations have Begun

I knew I probably needed to get going on the neck, but I really wanted to begin the back plate graduations, so I started in. This is about as far as I got. I will probably complete it tomorrow, but my hands were getting tired, and I needed to do something easier for a bit.

Back Plate Progress

Back Plate Progress

 

Neck Beginning

You may recall that the neck block had been delivered to me in a trapezoidal cross-section. This is quite common, but it poses a problem for me, because, once I have the side profile of the scroll and pegbox laid out, I prefer to drill a pilot hole for each peg, using my small drill-press, so that the holes are all perpendicular to the centerline of the scroll. That is hard to do, with a sharp angled shape. So, I set my bandsaw for 1/4″, and sawed off a triangular slab from each side of the big end of the trapezoid, reversed them, and glued those slabs back onto the sides, near the thinner end of the trapezoid. I checked with my little square, to make sure I had them at an appropriate location, then clamped them home. Once the glue dries, I will square up the block, lay out the neck, drill the holes, and get going on carving the neck. Those wedges will be completely removed, long before the neck is done.

Slabs removed and rotated up to square up the neck billet.

Slabs removed and rotated up, making it possible to square up the neck billet.

 

Slabs glued and clamped.

Slabs glued and clamped. When the glue is dry, I can square the billet, and proceed with neck layout.

 

A Break-time Treat

Ann and I decided to take a break and go for a walk, as Spring seems to have arrived early. As we neared home again, a pair of Bald Eagles passed by, flying low over our place, and landing in the trees at the front of the property, on the far corner. I had never before heard eagles “chatting” with one another. It was interesting hearing their clear, high-pitched chirps, and whistles, as they “talked” back and forth.

One of them almost immediately re-located to a thicker stand of trees across the road, but the other obligingly remained in sight, preening herself, until a passing hawk began diving at her, and she, too, moved into the thicker cover. I only had my cell-phone, but I did manage to get one photo.

Eagle in the distance.

Eagle in the distance.

 

Back to Work:

Squaring the Neck Billet

Once the glue was dry, I could square the billet, by sanding or planing off excess wood. Removing those slabs had left me with a few milimeters extra on the thickness, and much more on the depth, from front to back. So, since I had tried to plane it, but it tore out badly (as curly maple frequently does) I straightened the sides using the oscillating spindle-sander, and then laid out the neck details. I have made a new neck template, but it is just thin plastic. I will eventually make a light aluminum template which will be more durable. I first laid out one side, including the locations for the peg holes. Then I drilled the 1/8″ pilot holes for the pegs and cut the profile out on my small band-saw. After that, I was able to lay out the other side, and all the rest of the details; including the width of the heel, the width of the button, the width of the neck at the nut, and the taper of the pegbox into the actual scroll.

I forgot to take photos during that step (sorry) so all I can show you is the sawing procedure I used to remove the excess wood from the scroll:

Dcroll carving, first step.

I cut tangents to the curves, down to the scroll outlines from both sides.

 

Curve sections ready to remove.

Once I have cut sections all the way around, I can easily remove those sections and begin carving.

 

I will try to complete the back plate, the bass-bar, and the neck/scroll tomorrow. If I get that far, I will feel as though I am “on the home stretch,”, as the neck-set will then be the only difficult step left to do. We’ll see, though. There may be other priorities to pursue.

 

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Completing the Front Plate

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Completing the Front Plate

Completing the Graduations

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.

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!

Completed front plate interior, before f-holes and bass-bar.

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.

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.

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.

Edge-crest line, and gouge, beginning channel.

 

Beginning the Channel

Beginning the Channel

 

Channel is cut: now scraping can begin.

Channel is cut: now scraping can begin.

 

Treble-side scraping is nearly complete.

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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5-String Progress #10; arching the back plate

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Five String Progress #10: Arching

Completing the back plate arching

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:

Back arching done

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:

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:

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.

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.

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.

Beginning the inside arching, using a gouge again.

 

I will post again when I am ready to install purfling.

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