F-Holes and Graduations

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F-Holes and Graduations

F-hole Incision and Final Arching

In my last post, I told you I would “talk about F-holes, next time”…and we are doing so. But final arching, as well as graduation have to be completed before we actually cut out the f-holes, so, first things first:

I lay out and incise the f-holes after the arching is (mostly) completed, but before beginning any graduations. (I had a few mishaps years ago, when I graduated first, and subsequently discovered that my plates were actually too thin where the f-holes were to be laid out. I learned from the error, and I check the thicknesses around my already-in-place f-hole incisions, before beginning graduation, now.)

I laid out the distance from the upper edge of each plate to where the bridge would go. That is where the inner “nicks” of the f-holes will go. I measured back from there to find where the inner edges of the upper eyes of the f-holes would go, and laid out not only that longitudinal position, but the lateral distance off center, to the inner edge of each eye. Then I repeated that process for the inner edges of the lower f-hole eyes, and I was ready to use a template to scribe in the actual perimeters of the f-holes. I simply aligned the clear plastic template (traced off the full-size photos of the original instruments) so that the inner nicks were on the bridge line, and the inner sides of both upper and lower eyes were at their correct locations. I pressed the template firmly, so that it followed the curvature of the plate, and traced with a very sharp pencil.

I try to bear in mind that the pencil line will actually be “inside” the actual footprint of the f-hole, and I will remember to adjust it later. For now, however, I incise the perimeter of both f-holes fairly deeply, so that the marks will not disappear as I complete the final arching. (In the photo below, I had also traced around the incision with a very sharp pencil, to highlight the cut, so I could see it from any angle. Otherwise it can be hard to see.)

F-hole layout and incision — F-holes laid-out and incised.

Final Arching

I have learned that arching is one of the most important factors in violin sound. I use two “markers” for determining the final arching.

The first: I can see that, when viewed from the side of the instrument (at least, the ones I am concerned with), the f-holes on the old master instruments appear to have the main stem nearly parallel with the plane of the ribs. I have no idea whether that is truly important as far as aesthetics, but, I have also observed that, when left to my own instinct (or lack thereof) as to proper arching, my f-holes invariably end up resembling an “S” laid on its side. So, it is a “marker” that tells me my arching is a bit “off”, if nothing else. That is why I incise the f-hole perimeters deeply enough so that I can adjust the arching to get the stems of the f-holes parallel to the rib-plane, and be fairly sure that, at least that part is better than it was before.

The second “marker” is even more mundane: I made “arching templates,” traced from the posters, so that I can actually check and see that my arching closely follows that of the old masters. It is fascinating to me, to see them drop into place, one by one, as I carefully plane and scrape away the last few “humps”. I know that many makers are convinced they do not need such a “crutch”, but I see it as only a tool. I would never claim to be able to draw a perfectly straight line by eye and hand alone, and I shamelessly use a straight-edge for such a task. Arching templates are the same thing, in my estimation. Whenever I use them, even on a plate that I thought to be very close to correct, I invariably discover that it was not as good as I thought it was.

Using arching templates and scrapers to perfect the arching contours

The truly-completed arching is not terribly different than the rough-arching I had completed before incising the f-holes, but that sort of difference can make the difference between “acceptable” and “extraordinary” sound. When I first began using such templates, I immediately got a different response from players. They said, “This one is different! Whatever you did on this one, do it again!” (Okay…will do!) So…now I do it on every single instrument, and try to make each one better than the one before.

Graduation

What we call “graduation” is simply the process (and results) of carefully carving the inside arch to match the outside arch, leaving a specified thickness between, which could all be the same, or they could vary according to some sort of deliberate scheme designed to project well, or to give superior sound in some other way. Or it could be following a “general plan,” but, beyond that, be fairly random. There are all sorts of patterns and plans.

In this case I attempted (at least in a general way) to mimic the graduations of the original old master instruments whose pattern I was attempting to follow. (In case you have not read the previous installments, these two are to be modeled after the 1715 “Titian” Stradivari instrument and the 1735 “Plowden” Guarneri del Gesu instrument, respectively.) Their graduations are pretty thin, so this is a little scary, to me. I hope it works well.

I use a gouge to rapidly carve out the rough wood, until I am approaching the proper thicknesses, but then I switch to a toothed finger-plane for rapid, but controlled, wood removal. When I am getting close enough that I am fearful of going too far, I switch to a non-toothed curved-sole finger plane and carefully bring the thicknesses down to my target measurements.

Planing rough graduations, using toothed finger-plane

Two plates with graduation completes. — Two plates with graduation completed.

F-Holes

The F-holes are pretty much “locked-in,” now; the only thing remaining is to actually remove the wood inside the f-hole lines. The first order of business is to remove the circular portions at the upper and lower eyes of each f-hole. For this, I use a tool called an “f-hole drill”, which my grown children purchased for me a few years ago. It makes perfectly round holes, ranging in size from 5.5 mm up tp 10 mm in diameter, in 1/2 mm increments. I center a 3/32″ diameter hole in the center of the round portion of each eye, and then, using the correct bit, I insert the guide pin into that hole and gently rotate the tool to incise the hole, forst from the outside, and then from the inside, to prevent splintering, but completing the cut from the outside, so that in case any splintering does occur, it will be on the inside.

F-hole drill with cut-out plug from lower f-hole eye.

All f-hole eyes cut: ready to remove remaining wood.

Then I use a very thin, sharp knife to complete the incisions around the perimeter until the wood pops out cleanly.

Completed f-holes, ready for cleanup and final shaping.

I will continue to fine-tune the shape of the f-holes up until I begin varnishing, but, for now, they are complete.

The next thing will be the bass-bar in each top plate. The bass-bar supports the bass-side foot of the bridge, and the bass side of the plate. It is necessary in order to achieve the rich deep tones on the bass side of the violin range. So…next time: bass-bars!

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February 3, 2018February 3, 2018

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:

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.)

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.

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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January 31, 2018February 1, 2018

F-holes and Purfling

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F-holes and Purfling

F-hole Layout

I had to make a new template for the f-holes of the Guarneri model. I thought that I had made one some time ago, but if I did, I guess I must have misplaced it. I measured the image on the poster, to make certain that it matched the dimensions of the technical data on the back, and it turned out to be quite accurate, so I procured a piece of thin, fairly stiff, clear plastic (also called “re-cycled blister pack” from some sort of hardware I had bought), and laid it flat on the poster, and traced the outline of the hole with a ball-point pen. Then I traced the lines with a small sharp knife, until I was able to pop the waste plastic out, leaving a very nice template.

I laid out the “mensur” (sometimes called “stop-length”) on the front plate, for the bridge location, then began to lay out the relative positions of the upper and lower eyes. I had the data sheet to tell me how far apart they were to be, how far off center, and how far from the outer edges of the plate. I simply pushed it this way and that, until everything was according to the data sheet, and then traced the f-hole onto the plate, using a very sharp pencil. Then I flipped the template over and repeated the process on the other side. I double-checked everything, to make sure the layout was correct, cleaned up a few details, and was ready to incise the outlines of the f-holes.

F-hole layout complete. Ready to incise the outlines.

Incising the F-hole Outlines

I am only incising the hole outlines at this point, not making any attempt to cut them out: I have found that there is always a small flaw in my archings, in that they are always a little too high at the lower end of the f-holes. The result is that, if I look at them from the edge of the plate, my f-hole outlines look like a letter “S”, laid on its side, whereas when I look at the side view of any of Stradivari’s or Guarneri’s instruments, the stem of the f-holes seem to be nearly parallel to the plane of the ribs. So, to correct this anomaly, I lay the holes out so that they are correct, looking from the front; then I incise my outlines deeply, and finally plane and scrape the “south” end of the holes until the stems look correct from the side. The front view remains unchanged, and now it looks good from the side as well. Here is a “before and after” comparison:

Side view of F-hole before correction. — Side view of an F-hole before correction.

Side view of F-hole after correction. — Side view of the same F-hole after correction.

Beginning the Purfling Slot

The tool used to mark the location and dimensions of the purfling slot is called a “purfling marker,” or, fairly commonly, a “purfling cutter.” I suppose that, because there are two sharp blades on the tool, which are carefully set to the correct distance apart for the width of the purfling slot, and the correct distance in from the edge of the plate, it probably seems logical to call it a “cutter.” But the fact is, the tool does not work well for that purpose, and it works very well for just creasing the surface of the plate, thus scribing a double line virtually all the way around the plate. Usually the corners themselves must be laid out separately, either by hand and eye, or, by using a special template. (I have done both.)

Here is the tool, viewed from the edge, so you can see the two blades. There is a pair of small set-screws that hold the position of the twin blades.

Purfling marker blades. The blades are set for the width of the actual purfling, and the desired distance (4 mm, in this case) from the edge of the plate.

Purfling marker in use. The rounded brass shaft is pressed tightly against the edge of the plate.

Once the slot is marked all the way around, and I am satisfied with the look of the corners, I begin incising the purfling slot. The first time around, I am barely deepening the lines left by the marker; essentially just “darkening” those lines. The second time around, I press a little harder, cutting a deeper path through the wood. After that, I can cut as aggressively as I need to, and not have to worry about the blade being “turned” by a hard winter-reed, and marring the plate. This practice is especially important on the front plate, which invariably of spruce: The summer grains in spruce are very soft and easy to slice. But the winter grains (or “reeds”, as they are called) are much harder, and it is very easy for a harder, winter reed to turn a blade that is trying to cut too deeply from the start. (Hard experience speaking, here.)

Lightly tracing the outlines of the purfling slot, with a thin, sharp blade. — Lightly tracing the outlines of the purfling slot with a thin, sharp blade.

Initial outline incised. — Initial outline lightly incised. Ready for final cuts, and removal of waste wood.

Picking out Waste Wood from the Purfling Slot

After cutting to the approximate depth I want the purfling slot, I use one of several tools to pick the waste wood out of the slot between the incisions: any of them could be called a purfling pick. One of them is actually a 1/16″ gouge, made by the now-defunct Millers Falls tool people (at least, if they are still in business, I have lost track of them.) One is a tool I made for myself, attempting to achieve an easier, higher-quality cut. (It’s not that great, but it works…I can’t find it, now anyway….) The third is an actual “purfling pick” made by a commercial tool-maker. (I have had other such tools, which were functional to varying degrees. Some I eventually set aside because of poor-quality steel. They wouldn’t hold an edge.) So here are photos of the two I regularly use:

Purfling picks — Top tool is a purfling pick from Howard Core Co., and the bottom one is a 1/16″ gouge made by Millers Falls Co.

The idea, ultimately, is to end up with a slot into which my purfling will easily fit, but with very little extra room. I want the glue to swell the wood a tiny bit, and make it fit tightly, when I glue it in place. I also want my corners to look good. There is a reason they are frequently called “bee-stings.” I want them to be sharp and clear, and pointed in the right direction.

Using the purfling groove cleaner, (AKA “purfling pick.”)

Purfling slot completed. The dark dot at the top is hide glue, where I repaired a “slip.”

Installing Purfling

I make certain the slot is the right width and depth, checking it with a piece of scrap purfling, then I cut and bend the purfling to fit, giving special attention to the mitered corners. Finally, I remove one section at a time, slip hot hide-glue into the slot, using a thin palette-knife, and quickly re-insert the section of purfling, using a special roller to press it to the bottom of the slot. Once I have all six (four on the back plate) sections installed, I clean up any excess glue, and set the plate aside to dry.

Checking the depth and width of the purfling slot. I want the purfling to end up just below the surface of the plate.

Purfling cut, mitered, bent and inserted into the dry slot. the top center will be removed when the neck mortise is cut.

Purfling glued and pressed into place using the roller. — Purfling glued in place, pressed to the bottom of the slot, using the rollers in the picture.

The back plate is prepared in exactly the same way, except that I like to make the upper and lower purfling sections in one piece on the back. On the front, the top and bottom will eventually be removed when I cut the neck and saddle mortices, so I stop the purfling near the center at the top and bottom of the front plate. In some ways, the back is easier, in that the blade does not tend to wander as easily; but the maple is just a great deal tougher, too, so it is more physically demanding.

Next time, we will (maybe) talk about the final edgework, marking the crest of the edges, and fairing the curve from the bottom of the purfling channel up onto the curvature of the arching. But perhaps carving out the interior would be more appropriate. 🙂

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January 6, 2017

3/4-Size Violin Progress

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3/4-Size Violin Still in Progress

Last time… if you remember… it looked like this:

F-holes and Bassbar

So, I went ahead and cut out those f-holes, using an f-hole “drill” my children bought for me, and an X-acto knife.

Then I chalk-fit a bassbar blank, and glued it in place, using special clamps made by Jake Jelley, the friend who encouraged me to continue building instruments.

Bassbar blank with clamps. You can see the f-holes cut out…they still need more trimming.

Shaping the Bassbar

I carved and planed and scraped the bassbar into what I judged to be an appropriate shape for this instrument. Both it and the f-holes will receive a bit more scraping and shaping before they are varnished. The whole instrument, actually, is fair game for tweaking, refining, and perfecting, until the varnishing begins.

F-holes, bassbar and graduations nearly complete. Outer edges have been rounded to approximate their final shape.

Installing the Front Plate

I aligned the front plate as closely as I could with the rib garland, and applied six spool clamps–one for each inner block. Then I loosened one clamp at a time, and, using a thin palette knife, I slipped hot hide glue between the plate and the blocks and linings. I rinsed the edge, overhang and rib quickly with hot water, and wiped it with a rag, then re-tightened the clamp, and added more clamps between that clamp and the next, repeating the procedure untill all the edges and especially all the blocks were securely glued and clamped, and relatively clean.

Front plate installed, using spool clamps. Ann thinks these look like hair-curlers. 🙂

Back view of mold with front plate installed, and spool clamps. The mold will be removed after the neck is set.

Purfling Comes Next

Not everyone does things in the same order. I have had trouble, in the past, getting my edge overhangs even all the way around. If I install the purfling first, then I am locked in, so to speak, and if the overhang is uneven, there is nothing much I can do. But if I purfle after installing the plate, I can take time first to adjust that overhang, using files and scrapers, until I am satisfied that it is the way I want it, and then purfle, following my adjusted edge shape.

Installed front plate, from the mold side, showing the overhang. Notice that there are no back linings, yet.

Purfling laid out and lightly incised. (The shadow is my head– I was too close to the plate.)

The idea at this point is to just deepen the lines a bit, not to try to cut the full depth of the purfling slot. You can see that, in some places, the waste wood begins to pop out on its own. Most will have to be removed using a purfling pick. Here is a closer photo of the incised purfling lines:

Close-up of the incised purfling lines. That corner will still undergo significant shaping and refining.

So…next time, I will show the completed purfling, and the neck-set– I hope. 🙂

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September 10, 2016September 10, 2016

More Progress on the 14-inch Viola

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More 14-inch Viola Progress

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.

Completed neck-mortise — 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.

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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September 7, 2016September 7, 2016

Progress on a 14-inch Viola

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Continuing on the 14-inch Viola

Arching and Graduation

The outside arching for the front plate is essentially complete, though there will be a lot of scraping, later on. I began the graduation (inside arching) of the front plate about the same time as I took off and “sprinted for the finish line” with the “Plowden” Guarneri-model violin (see recent posts), but all I accomplished was that the center of the plate is about the right thickness– everywhere else it was still way too thick.

So! Back to work! You can see (below) that the f-holes have been laid out and deeply incised, which allowed me to accomplish the last stage of the front arching (explained in an earlier post.) Now I need to carefully carve away the interior, until all the plate is the thickness I want it to be…which varies by region, all over the plate. I have to be very careful to check certain areas with a caliper before I begin to carve, or I may easily go too far and make the plate too thin. (Voice of sad experience….) The area around the lower ends of the f-holes are very likely victims of this error, so I try to check regularly, and avoid carving away too much in those areas, especially.

Outer arching small viola top — The outer arching of the small viola is complete, not counting the purfling channel.

Side view of small viola arching, before purfling and edgework. — Side view of the small viola’s arching, before purfling and edgework is done.

Inside arching of the small viola. The Graduation is complete. Next, I need to cut out the f-holes, and add the bass-bar. I do realize the corners are too long…I will trim them later.

Coffee Stain

One thing I decided on this instrument was that I should begin the coffee staining very early, so that, if there is any distortion, due to the wetting of the wood, I can correct it before the plates go on the garland. In this photo, it is hard to see how much the grain is raised, but, those wide summer grains of the Sitka Spruce are all swelled up like corduroy!

I will let it dry, and then gently scrape it smooth again. The issue, here, is that the summer grain swells more than the winter reeds, but when we scrape the wood, the summer reeds compress, while the winter reeds resist the blade and are cut away. The result is that the summer reeds are already raised, even before I wet it down and deliberately raise the grain, before leveling it again.

Things remaining:

When the plate is nearly perfect all over, I will finish cutting out the f-holes, and finish their edges as well as I can. I nearly always see something later that I have missed, so I just accept the fact that I will be making corrections right up until the time I begin varnishing. The same thing applies to the scroll. It will never be “perfect”, and I accept that.

I will lay out and fit the bass-bar, trying for an air-tight fit between the bass bar and the inside of the front plate. I install it using hot hide glue and clamps, but will trim it to the proper shape after the glue is dry.

After the bass-bar is fully completed, I round the inner edges of the front plate, so that it is ready to install on the garland.

Post Script:

All of the above was accomplished three weeks ago, before we left on vacation, so it should have been published then, too…but I kept thinking I would get a little more done before we left, so it simply did not happen.

We are back, and progress is once again happening, so I will post more in a day or two.

Thanks for looking.

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July 31, 2015August 1, 2015

5-String Fiddle Progress Report #5: F-holes and Bass-Bar

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F-holes and Bass-bar

F-hole Drill

We had just completed the graduation in the last post; Usually, by this point, I am beginning to see the interior of the f-holes, too, because, as you may recall, I had incised them pretty deeply. In this particular case, I could just barely see some portions. I guess they were not as deep as I thought they were.

Once the inside is complete, I finish cutting the f-holes. Many people use a jeweler’s saw, a fretsaw, or a coping saw to cut out the f-holes. I generally just use the knife, except that I do have a special tool for cutting the round upper and lower eyes. I didn’t take any photos of it this time…here is one from an earlier instrument:

f-hole drill and holes — F-hole drill with completed eyes and cut-out plugs.

F-holes Completed and Clean

Just getting the f-holes cut is only part of the job…they need to be clean, and smooth, and relatively symmetrical. I will keep touching them up and tweaking them until the day I begin the varnish, most likely, but here they are; close to being complete, if not completely done.

By the way, you may have noticed that on this instrument (and the last one) I purfled after installing the plates. I was taught to purfle early, but I always had trouble getting my overhang even, and my purfling parallel to the ribs. So I tried purfling after closing…works fine and looks better. Diff’rent strokes, I guess….

Bass Bar

When the f-holes are complete, and clean, I can fit the bass-bar. The bass-bar is a spruce brace supporting the bass-side of the bridge, and providing for a good sound on the low strings.

I lay out the location of the bassbar, 1/14th of the width off center, at both upper and lower bouts. It usually ends up about 15 mm off center at the lower bout and 12 mm off center at the upper bout. (Those were the exact measurements this time: the upper bout was 168mm wide and the lower was 210 mm wide. So 1/14th of each was 12mm and 15mm respectively.) When I lay the bass-bar blank along that line, the side of the blank should just about “kiss” the upper eye on the bass side. I make slight adjustments as needed to make sure it does not obstruct the f-hole at all, then scribe the line in with a flexible steel ruler and a soft pencil. The line ends 40mm from each end of the plate, so the bassbar is just under 11″ long, (and about 7mm thick where it contacts the plate, tapering to 5mm along the free edge.)

bass-bar layout — Bass-bar layout lines complete.

Chalk-Fit Trick

Then I do something a little unusual: lots of luthiers chalk-fit bass-bars…in fact, probably most of them do. I have only known one or two who can successfully “eye-ball” the thing in. But I do not like the looks of chalk-residue mixed with hide-glue, either. I can’t see the white chalk clearly enough to use it, and the others leave an ugly residue– expecially the green or blue chalks.

So… what to do? Someone, years ago (can’t recall who…probably my friend Jake Jelley), pointed out that the paper gauze tape sold in pharmacies will stick securely, you can see the line through the tape, and it holds the chalk very well. The tape (3M Micropore) is so thin and fragile that you get a very good fit, but when you take the tape off after the fit is perfect, all the chalk comes off with it. (Careful! It can pull splinters off, too!) Hey, Presto! Clean wood, and you are ready to glue in the bass bar!

Pre-Fitting the Bar

I pre-fit the bass-bar by eye, using a compass to mark the contour from both sides, then trimming with knife and plane until the fit is close.

Bass-bar pre-fit. — Bass-bar pre-fit by eye, using a knife and plane to trim the wood to a close fit. Chalk-fitting is next.

Then I apply the paper tape, darken the line on the tape as needed, and begin the chalk-fit process. It is important to learn to JUST plane or scrape away the portion of the bass bar with chalk on it, on each try. Don’t plane off whole sections…it is possible that only that one little place with the chalk was high.

paper tape for chalk fit. — There is the paper tape…you can still see my layout lines.

chalk-fitting bass-bar — Beginning chalk-fit.

chalk-fit complete — Chalk-fit complete, and tape removed. Notice the arrow on the upper end of the bar: that is to keep me from forgetting which end is which.

Final Check and Installation

I check the fit by clamping the bar in place, dry.

bass-bar dry fit — Dry fit and clamped for final check. Seems to fit acceptably…

Then I remove the clamps, and slather on the hot hide glue–carefully. I quickly re-position the bar and clamp it securely, then clean up, using hot water and a brush. The small amount of watered-down glue soaking into the wood around the bar doesn’t seem to hurt anything, so I don’t worry about it.

bass-bar glued and clamped — Bass-bar glued, clamped and brushed down with hot water.

Shaping the Bass Bar

When the glue is completely dry, I remove the clamps and shape the bar…”just so”.

sketched shape of bass-bar — The glue is dry… see the sketched-in proposed shape of the finished bass-bar. The dark area beside the bar is just a shadow, not glue.

I do not have a “scheme”, here, and I do not measure it beyond occasionally checking the center height. I am just going by feel, by eye, and by experience. I know if the bass bar is too weak, it will affect the sound of the bass string…so I err on the side of a tall bar. I am certain that many will frown upon this. I am not telling you how you should cut a bass-bar; just sharing how I handle mine.

So; I use gouges and finger-planes initially, to shape the bar, finishing up with scrapers, files, and even sandpaper. (Yes, I know…but it’s OK, honest!)

And…there’s the plate, completed and ready to install! Well…sort of….

The glue was a little too thin on one end of the bar and it popped off for about a 2″ section. So it has been re-glued and is drying.

bass-bar nearly complete — Bass-bar nearly complete. One end popped loose, and needed re-gluing.I will do a little final shaping before calling it done.

Besides, the inner edges of the plate will have to be rounded and smoothed before I can actually install it. But there are probably less than 30 minutes of work left before I can glue the front plate in place. So it’s almost done. I hope to install it tomorrow, but I have some other things to do, as well.

Some of you may wonder why I install the front plate first; I was actually taught to do the back plate first, and to install the neck last, but it finally occurred to me that I could fit the neck before installing the back plate, and before removing the mold, and get a perfect neck-set, then trim the back of the heel flush with the rib plane, and install the back last, after removing the mold and cleaning up the interior. It worked very well, so I have continued the practice. Again; different ways of doing things result from different skill-sets and different problem-solving methods. There is nothing wrong with either way. (I even knew of a fellow who set the neck before installing either plate…but I can’t see that one. On the other hand, that guy made over 1000 instruments before he died, and sold every one of them; he must have been doing something right.)

So, the next post will involve completeing the neck and fingerboard assembly, installing the front plate, and setting the neck. Could be a week away; I am going to be working a lot of overtime on my day-job, for the next several months it seems.

Later the same evening:

finished bassbar 1 — Bassbar is finally complete!

bass bar side view — Side view…lighting is difficult, but you can see the profile.

Thanks for looking.

Chet

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July 29, 2015

Five-String Fiddle Progress Report #4: Graduation

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5-String Progress Report #4

Graduation

Graduation begins with measuring in the spots where it already feels a little thin, so as not to make a fatal mistake and carve right through the plate. (It happens!)

Once I know where I am free to carve, and where I need to take it easy, I begin by carving cross-grain with a medium-large gouge. I check periodically with a caliper. When it begins looking closer to the right shape inside, I measure again, and double check those special spots.

carving inside violin front plate — Beginning graduation, using a gouge.

Then I go after it with a toothed finger-plane. This is really just an Ibex 18 mm finger-plane with a toothed blade, and a wooden handle added to save my fingers. I originally added that handle to keep from blistering my forefinger and thumb, as I had done so on every single instrument up to that point. (That was my #16 instrument– a cello.) I was surprised to discover that it also gave me much more power and control so that I was able to set the blade deeper and carve much more aggressively, taking off much thicker shavings.

Toothed plane use — Using a Toothed Finger Plane to further the Graduation process.

Once it is smooth inside, and within a millimeter or so of completion, I switch to a smaller finger plane and cut more gingerly, until it is all within a few tenths of a millimeter of the goal thicknesses, and then I finish with scrapers. Here is how the plate looks at that point:

graduation...inner arching. — Graduation nearly completed– the skewers are only there to create shadows so that the contiour will show in the photograph.

inner arching. — Another view, at a lower angle. There are still a few lumps to smooth out, but the graduation is essentially complete.

Usually, by that point, I am beginning to see the interior of the f-holes, too, because, as you may recall, I had incised them pretty deeply. Once the inside is complete, I finish cutting the f-holes. Many people use a jeweler’s saw, a fretsaw, or a coping saw to cut out the f-holes. I generally just use the knife, except that I do have a special tool for cutting the round upper and lower eyes.

And that is what I will show in the next post…which, hopefully will be sooner this time.

Thanks for looking,

Chet

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July 15, 2015

Five-String Fiddle Progress post #3

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5-string progress #3

Arching and F-holes

Last time, I had traced and cut out the top plate, and actually, I began the work on it, thinning the plate to the desired arching height– but that is when I discovererd that there was a bark inclusion that extended right through the upper bouts. So, for those “sharp-eyed” among you, who notice that the grain has changed; Yep. It surely has! Too bad…I liked the grain of the spruce in the plate I first chose, but it turns out it was just a little too interesting.

So, on this plate, all I have done is the outer arching and the layout and incision of the f-holes. After completing the arching, but before final scraping, I laid out the distance from the upper edge of the plate to the “stop” line (where the bridge will stand) at 195 mm, then laid out the distance between the upper eyes at 42 mm. I used a plastic template that I made years ago (cut out of an old flexible face-shield– the kind welders use when they are grinding steel) to lay out the shape of the holes, then incised them deeply with a thin knife. They would have been virtually invisible in the photos, so I traced them again with a sharp pencil after incising them, so that you could see them in these photos.

Arching and f-holes — Arching complete, f-holes laid out and incised.

Arching: Final Check

Next I checked the arching by sighting edge-ways at the plate, to see whether the main stem of each f-hole is fairly parallel to the rib-plane. Usually I find that I have left the arching a little too “puffy” around the lower stem and lower eye area of the f-holes and need to plane away a few more strokes to get the stems lined up. I don’t think the looks of the f-holes are the main issue, here– the shape of the arching is fairly critical to the sound, as best I can understand, and this is just a “marker” for me to check.

Side view of f-holes. — Checking to see that f-holes are aligned with rib-plane.

Obviously, this alignment is something I have to do before I try to complete the inside carving, or there might not be sufficient thickness left to do the final adjustment. I try to estimate and get this area as close to correct as possible before laying out the f-holes, but I have had to adjust them at least a little, every time, so far.

After I am satisfied with the overall shape of the arching, I use scrapers to reduce all the lines and ridges left by the finger planes into a smooth continuum.

Graduation: Beginning the Interior

Once I have the outside arching the way I want it, I can start on the inside, and the final graduation of the plate. I hold a pencil in my fingers so that about 9 mm protrudes onto the plate, and then run my fingers around the edges…nothing precise about it: it is just a guideline for carving. I want to leave this area untouched until the last bit when I am scraping the inside, before installing the bassbar. I use the same template that I use for the final shape of the end blocks to scribe the shape of the area to be glued to the blocks. I scribe in the corner blocks with a curved scraper that just happens to fit the shape I want. All this outer perimeter area will be left flat until the last step before installing the bassbar, and/or installing the plate on the ribs. I want just the gluing surface flat when I am ready to install the plate.

Inside front plate, before carving — Inside carving plan.

Preparing for Graduation: Measure First!

It pays to use a caliper and check the thickness all over before beginning to carve. I do have a mental image of the desired shape of the interior, but I do not have a mental map of the thickness of the plate, so I measure at least the areas that already feel pretty thin to my fingers, and decide how much should come off in each area. As it turns out, this time, no areas are really borderline, but some are within 1.5 mm or so, so I will be careful around those places. I am aiming for about 3.5 mm down the middle, fairing down to 2.5 in the upper and lower flanks. and a few places 2 mm, very likely. I will try to leave some areas a little thick, where there is a likelihood of cracking, but in general, I expect this will be a pretty thin plate…the spruce is a little dense (which I have had good results with in the past), so it can stand to be a little thinner than usual.

After the inside is carved and scraped to my satisfaction, I will complete the cutting out and shaping of the f-holes, then chalk-fit and install the bassbar. I will post photos of all that.

Thanks for looking.

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