Posts Tagged ‘gouge’

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. 🙂

 

Thanks for looking.

 

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Beginning Graduation (inside carving)

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Beginning Graduation (inside carving)

How Thick?

This becomes another critical issue: How thick should the plate be at any given point? I will try to follow the poster to some degree, but it was only correct for that particular instrument, with that particular set of plates. The wood I have may not be anywhere close to the same stiffness or density, so I have to get into some sort of “ball-park” range, and then start making decisions based on this wood that I am carving. How it feels, how it flexes, how it sounds when I tap on it, all make a difference in my mind, though I am aware that there are some standard thicknesses to which many makers adhere.

Others measure the vibrations of the nearly completed plates using a frequency-generator, and try for certain frequencies to make a certain set of patterns (called eigenmode frequencies, and nodal patterns, or Chladni patterns). I have tried this and couldn’t get it to work for me. Then, one day at a workshop, one maker was haranguing me that I wasn’t graduating my plate correctly, and took me out to the plate-shaker thing, and demonstrated to his satisfaction that I had it “all wrong”. I had simply followed some graduation thickness numbers given me by a master maker (who does not want me mentioning his name), so I could not tell him that. I was feeling pretty glum about the whole exchange, when he looked up and saw another maker coming in, who he considered to be an expert at testing plates. He said “Ask him! He’ll tell you!”

So, the other fellow obligingly came over and began setting up the plate-shaker, while the first guy stalked off.

I noticed that the second guy did not set it up at ALL like the first guy had done, but I kept my mouth shut. He ran through the frequencies and numbers, and finally said, “It’s perfect! Don’t do another thing to it! Install the plate!”

So, I walked back into the work area, not intending to say a word, but the first fellow was waiting for me: “Well?! What did he say??” I repeated, verbatim, the second fellow’s verdict. The first guy said “What??!! How come I got the numbers I did??” I replied, “I couldn’t tell you! I don’t know how to run that machine!” No more interference that week… 🙂

So…the point is, there are a variety of ways to achieve the goal of good plate graduation. That experience convinced me that even just following a set of established thickness values can work just fine. And, ultimately, that is probably about what I will do, on this violin.

Moving Wood

I began with a gouge, trying to get within a few millimeters of the right center thickness.

Beginning inside carving with a gouge.

Beginning inside carving with a gouge.

 

Then I switched over to a toothed plane, which I find more comfortable to use. The handle on it is a modification I added to shift the pressure to the heel of my hand instead of my thumb and forefinger.

Toothed plane progress.

Toothed plane progress.

 

Wooden handle.

The normal orientation of the screw in the Ibex plane (left) has been reversed to hold the wooden handle as well as the blade.

 

Repairs

But then I heard a cracking sound: Not a good thing to hear when you are working on a violin. I looked the plate over and could find nothing amiss, so I went back to moving wood. Heard it again, louder. (Sigh…)

It turned out my work-cradle had broken! (What a relief!) Well, I made it 15 years ago, and it has served well, so I took the time to glue it and insert three dowels, diagonally, through the break, to hold the joint against further failure.

Repair of broken work cradle.

Repair of broken work cradle.

 

Work Cradle construction.

Work cradle construction: a heavy pine plank with a cutout to support the margin of the plate. Thin plywood surrounds the plate-edge.

 

Back to work:

I am aiming for about 4 millimeters in the middle, and all over, which I will refine later to the specific measurements I want. In the photo, below, reading the dial on the caliper, you can see I am nowhere close. But…I’m tired, and I’m going to call it a night. By the way, in case anyone was wondering, those jagged-looking black pencil lines around the lower corners are outlining an area that was pretty close to the right thickness already: I don’t want to touch them until I am on the home-stretch where graduation is concerned. It is VERY easy to get too enthusiastic and carve too deeply in such an area, and ruin the plate.

Long way to go!

Long way to go!

 

So, next time, I hope to have the graduation complete, so I can cut out the f-holes and install the bass-bar.

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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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5 String Fiddle Progress Report #6: Front Plate Installation and Purfling

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Five String Fiddle Front Plate Installation

Back to Work!

It was fun working on the Sawmill, and just as we got that done our daughter came home (from Switzerland) for a visit, so, between that and all the overtime at work (teaching print-reading classes), it has been hard to get going again, but the fiddle has been patiently waiting on the dinig room table for me to get back to work.

Installing the Front Plate

I levelled the garland by scrubbing it back and forth on a sanding board, then aligned the plate on the garland and clamped it with spool clamps. After heating up the glue, I removed a few clamps at a time and inserted the glue with a thin pallete-knife, and re-applied the clamps. In this way, I can work my way around the perimeter, accurately and easily gluing the plate in place without fear that the glue will gel before I can get the plate clamped in place.

front plate with garland

Front plate glued in place

Ready to begin Purfling

The purfling is an inlay that is partially decorative, and to some degree a protection against cracks and splits– an edge reinforcement. There are some (usually very cheap) instruments that have the purfling simply painted on, so that it only looks good, but has no other function. They are usually seen as sub-standard, though, and I will not consider making an instrument that way…so, here is the beginning point: the purfling marker. Two blades set apart by the exact thickness of the purfling to be inlaid, and the distance from the edge set, as well.

Purfling marker

Purfling marker

Some people call this a purfling cutter, but it really does not workwell if you try to use it to cut the slot. I mark the slot with this tool and then cut the slot with a sharp, thin knife. In use, the purfling marker should be held exactly perpendicular to the plate, and tightly against the plate edge.

Purfling marker in use.

Purfling marker in use: see the double lines.

The purfling marker will not complete the corners, and they are fairly critical to the overall look, so I carefully sketch them in with a very sharp pencil.

Sketching the corners

Sketching the corners

Cutting the Purfling Slot

I usually use an X-acto knife to cut the slot, and pick the center out with one of several tools made for that purpose.

Purfling tools.

Purfling tools.

The first trip around the plate it is important to go lightly but very accurately, so that I am barely deepening the marks left by the purfling marker: after that I can cut more deeply.

Incising the Purfling Slot

Incising the Purfling Slot

Cleaning the Purfling Slot

After I am satisfied that the cuts are the correct depth all the way around, I carefully pick out the center of the slot and clean the slot, using a purfling pick. I have some that I made myself, but this one was given to me by Jake Jelley, and it works very well.

Purfling Pick in Use

Purfling Pick in Use

Ready to Install Purfling

Ready to Install Purfling

Installing the Purfling

Some people make their own purfling…maybe I will try it someday, but for now, I buy mine in three-ply strips. The strips are too brittle to bend, so I use a bending iron to make them flexible and to bend them to the correct curvature for the tight corners.

Purfling strips with prepared frot plate

Purfling strips with prepared front plate

 

I try to install the C-bout purfling first, then force the mitered ends of the upper and lower bout purfling against the mitered ends of the c-bout purfling. It takes practice to get good at this: I do not claim to have “arrived”. But it does seem to be getting easier. (I read the other day that someone asked Pablo Casals why, at 93 years of age, he was still practicing the cello for three hours a day. He said, “I think I am seeing some improvement!”) (Good one, Maestro!)

C-bout Purfling installed

C-bout Purfling installed dry

Then I install the rest of the purfling strips: I want the slots to fit snugly, but not so tight that I will struggle to install them once I apply the hide glue.

Purfling installed dry.

All Purfling installed dry. Spliced in some places, but after gluing the splices will be invisible.

Gluing and Trimming the Purfling

I lift each section up out of the slot, one at a time (tilting them, so as to try to leave the mitered ends in their places), and use the palette knife to slip thin hide glue into the slot, then press the purfling back into the slot, all the way down. I use a roller made for installing the rubber trim around window screens to force the purfling all the way home. The glue squeezes its way into the mitered corners, and secured them. The plastic roller is easy to clean afterward with hot water.

Once the purfling is glued in place, I mark a line around the margin of the plate, using a compass, with the pencil set to about 1.6mm (1/16″ or so), so that I have a guide to follow as I cut the “channel” (trimming the purfling below the surface into which it has been glued.) I want the wood surface and the purfling to make a smooth curve that begins near the edge of the plate, cycles down through the purfling, and sweeps back up to join the curve of the violin plate. I carve the channel with a gouge, then scrape to complete the curves. The faint pencil guide line can be barely seen in this photo.

Trimming the purfling and cutting the channel

Trimming the purfling and cutting the channel.

And there is the finished work, ready for the next step.

Completed Purfling.

All the purfling is trimmed, the channel is cut, and the scraping is complete.

The outer edgework will be completed after I install the neck. I used to wait and install the neck last, but I eventually decided that I prefer to install the neck and fingerboard while the front plate and rib garland are still on the mold, then trim the heel of the neck to be in plane with the back of the rib garland so that the back plate can be installed last. But that is a subject for another post….

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How I carve a Scroll

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Cello Scroll Carving Made Simple 🙂

There is nothing special about the way I carve scrolls. As far as I know, this is how everyone else does it, too, more or less. I am only sharing how I do it.

Start by tracing and sawing out the profile of the whole neck.

I don’t have a photo of the scroll as a simple profile, but I begin with the billet (About 6″ x 3″ x 20″), and trace my template onto it, then use a bandsaw to cut the shape of the profile. I use a oscillating spindle sander to remove the saw marks, and perfect the profile right to the line. While the profiled block is still “square”–that is, while the sides are still parallel, I lay out the peg hole locations and use a drill press to make 1/8″ diameter pilot holes where each peg will be. I drill all the way through, so that the holes are clearly marked, and are perpendicular to the center plane of the neck.

Next cut out the pegbox and at least a few inches of the neck

I hollow out the pegbox before carving the scroll proper. Some people use a drill to get started. I have done it this way, but it seems a little risky, unless you put some sort of limiter on the drill, to avoid going too deep– and even then it is easy to go out of bounds. I use a narrow chisel to remove most of the rough wood, then a wider chisel to smooth the inside cheeks of the pegbox. I also saw off the excess wood on the outside of the pegbox, and plane those faces flat.

Then draw the shape of the scroll itself.

Usually we use a template for this, as well. Some people plot out each scroll with a straight-edge and compass. I have neither the time nor the inclination. In this case, my templates came from a poster of the 1712  “Davidov” Stradivarius cello, now being played by Yo Yo Ma. Some information was lacking, and I filled that in from Henry Strobel’s book on cello making.

And begin cutting:

Once the scroll is drawn out, I clamp the neck to my workbench and, using a Japanese-style pull-saw, I begin cutting slots nearly to the layout lines of the volute. I rotate my position a few degrees, and make another cut. I have to be careful to avoid cutting too deeply, but this method allows me to chip away the waste wood rapidly, and the scroll begins looking like a scroll rather quickly.

Beginning the scroll, proper.

Pegbox is complete, volute partially carved. The cut lines are visible on the portion of the volute that has already been carved. Now we will carve the scroll, proper.

Cutting more kerfs to remove wood.

Care must be taken to avoid drifting across the line into the turns of the volute.

Cutting a series of kerfs for wood removal in carving a scroll.

You can see the direction this is going…I will continue to slice down nearly to the line, rotating a little each time, until I have gone all the way around.

Using a gouge to outline the eye of the scroll.

Once the kerfs are all in place, and to the correct depths, I use a gouge to outline the eye of the scroll, so as not to damage it with the saw.

Kerfs in place, and eye of scroll deeply incised. Carving can begin.

All the kerfs are complete, and the eye is deeply incised with the gouge–I am ready to start carving.

Use a flat chisel to remove the waste wood, and the scroll begins to emerge.

I use a flat chisel to remove the waste wood, and the scroll begins to emerge.

Once the waste wood is completely gone the

Once the waste wood is completely gone the “undercut” carving can begin.

Bi-lateral symmetry

I try to make sure the two sides match symmetrically, before beginning undercut. I do the outside fluting last, to avoid damaging it while carving other parts of the scroll.

Bass side of cello scroll, nearly complete.

Here is the bass side of the scroll, nearly complete.

Treble side of cello scroll, nearly complete.

And, here is the treble side.

Cello neck and scroll, nearly complete.

The neck and scroll are nearly complete. I will continue to fine-tune and scrape the scroll, perfecting it as best I can, right up to the day I begin varnishing.

Fingerboard installed on Cello neck, with hide glue and clamps.

I have prepared the fingerboard, and now I have installed it, using hot hide glue and clamps.

So– that was entirely enough for today. Tomorrow I will continue to refine the scroll and neck, and try to get the neck set. If I succeed, then I can remove the mold and install the back plate.

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