Beginning Two New Violins

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Beginning Two New Violins

First Things First:

I began by making sure that I had appropriate wood for both instruments: I wanted a one-piece back for the Guarneri model instrument, with deep flames sloping downward from left to right, and I wanted a heavily flamed two-piece back for the Stradivari model…both of European Maple, with ribs to match them, and European spruce tops. I had them, all right, so I bookmatched the two spruce tops, and the back for the “Titian” Strad attempt, and left them to thoroughly dry. Afterward, I visited my son’s guitar shop and used his power planer to flatten the plates, and bring them each down to the thickness I wanted for the arching height.

Prepared plates: European Maple and Spruce

Working Vacation

I took a week off from work, intending to “get a lot done” on the violins, but ended up sick for most of the week. Besides, Winter is coming on, and we needed to get firewood in, so Ann and I loaded and hauled and stacked firewood for a couple of days, and I got about two good days of work on the violins. During that time, I installed blocks in the molds, shaped them to receive the ribs, thinned and bent the ribs, and installed them. Last, I installed linings, to add stiffness to the edge of the rbs, and additional gluing surface. The ribs, like the back plates, are European Maple, but the blocks and linings are willow…not sure what variety. I like weeping willow the best, because it carves and bends so nicely, but other willows work well, too, sometimes.

Then, once I had the linings in place, I trimmed the rib corners to their final shapes, and flattened the front face of garlands, after which I used the garlands themselves to trace out the shape of the top plates. Finally, I cut out the top plates and shaped them to the exact outlines I wanted, and I was ready to begin arching. I will do the same thing for the back plates later.

All four plates, both garlands, with neck blocks. Strad model on the right, Guarneri on the left.

Slow Start

I didn’t get much of anything else done, this week, as I was at work, mostly, annnd, Thursday, some fellow failed to yield on a roundabout, and totalled my wife’s car, as she was coming home from the grocery store. The roads were very wet, which may have contributed to why he was unable to stop, and why the impact spun her car around, 180 degrees, and hurled it off the road, into a field, next to the roundabout.

Ironically, she had also just gone to DMV, and had paid $193 to renew the DEQ testing, and registration, as well as filling her gas tank, to the tune of $40. So all that was wasted, too, but she is completely unhurt, for which we are deeply grateful. Guess it is time for her to get a newer car. 🙂 There was also a dented can of beans, and two squashed bananas…but I ate the bananas, and tonight we ate the beans. No loss there. 🙂

This evening, however, I got home fairly early, and I got most of the arching done on the Stradivari-model top plate, so at least that feels better, in terms of productivity. I will try to complete it tomorrow and repeat the effort on the Guarneri top plate.

I will post more pictures later.

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November 27, 2015

Building a Double Bass: Shaping the Blocks

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Shaping the Double Bass Blocks

Lots of Wood to Move!

As you may recall from the previous post, the blocks on this upright bass were pretty huge, compared to what they needed to be, so there was really a lot of wood to remove.

Mold with blocks and ribs. Blocks are still way oversized, and the ribs are still straight. Gotta change all that.

“Kutzall” Tool

So! A drastic need makes for drastic measures. Ordinarily, on a smaller instrument, I would use the bandsaw and oscillating spindle sander to shape the blocks, but this mold is reeaaalllly heavy (over-built, I think…oh, well, it will be removed and the bass will be normal), even though it is a soloist bass, so I can’t see trying to manhandle it around on my big bandsaw. The saw could handle it, but the table for the saw is not big enough to hold the mold steady, and I am not strong enough to just hold it up there by sheer strength…. So… what to do?

This tool (carbide abrasive disc) is something my wife bought for me a year ago (Christmas), but I had never used it much. It is called a “Kutzall”, and it tears away wood incredibly rapidly, without loading up, and without burning the wood. So I used it to remove the large rough sections, then used the plane to remove the torn surface, and finally, to shape the blocks:

Kutzall disc, with 5″ DeWalt angle grinder: Not for the faint of heart! Absolutely wickedly effective, but not as dangerous as the Lancelot tool.

Stanley #100-1/2 Squirrel-tail Plane

It was about 37 degrees, F, outside, but the sun was bright, so I worked outside.

Smoothing and shaping the corner blocks, using a Stanley “Squirrel-tail” #100-1/2 hand-plane.

The little plane is somewhat hard to control, because the curvature of the sole is so extreme, but, if it is sharp and if the blade is set for a very shallow cut, it works well.

sharp plane — It ***does*** have to be sharp! (Time to sharpen….)

Stanley # 100-1/2 curved-sole plane…for those of you who are unfamiliar with it.

stanley plane — I was able to shape the blocks pretty close to finished shape with the little plane, but there are some irregularities. I have another tool for that problem.

The bottom block was planed entirely with a low-angle plane (also Stanley– can’t recall what number.) but it worked very well, and the bottom block was easy…I didn’t use the grinder at all on this one. So here are all the blocks, pretty close to finished:

Bottom block planed with a small, flat-sole, low-angle plane.

And, here you can see the finished blocks, ready for sanding:

All the blocks, ready for coarse-sanding. The small plane leaves ripples. The sanding tool should remove them all.

Homemade PVC Sanding Tool

As I mentioned earlier, the oscillating spindle sander I have would not be tall enough for these blocks even if I could manhandle the mold up onto the machine. So, I made this little sanding tool out of re-claimed PVC fittings from the “Habitat for Humanity Re-Store”, and spent more on the little can of PVC cement from the hardware store than I did on all the other materials…about $2.50 at the Habitat store. I used PVC cement to affix the abrasive cloth to the pipe, too, and bound it up with strips of plastic bag until the solvent outgassed and the cement was set.

PVC sanding block — Sanding block fabricated from four PVC fittings and a 2″ section of 2″ PVC pipe, with a little piece of wood for the handle grip. Comfortable, efficient, and cheap.

The homemade sanding tool worked extremely well for the small corner blocks, and did very smooth work. On the neck block I used it cross-grain, holding the tool parallel to the “trough” of the curvature, and sliding it up and down the curve. It worked well, there, too, just not as perfectly as on the corner blocks. All in all, it is a very satisfying tool.

Sanding corner blocks. — Sanding the corner blocks.

Sanding the neck block, I kept the block parallel to the “trough” of the curve, and pushed it up and down, across the grain to get a smooth surface.

Change of Plans

You may have noticed that, though I had planned to use Willow for blocks and linings, those blocks are not willow: the corner blocks and end block are all Douglas Fir, and the neck block is laid up of three layers of clear, vertical grain Sitka Spruce. It was a matter of availability. I do have willow for the linings, and, as that in my preferred wood when I have a choice, that is what I will use. It cuts easily, bends easily, and is very pleasant to work with for both linings and blocks.

I have really felt that I was “spinning my wheels” on this project. It is large enough that I feel the necessity to work outdoors whenever possible, but the weather has not cooperated very well…it rained nearly every day for the last month. In addition, I have been struggling with a cold or some such virus. Today I was cold in the house when the thermometer read 75 degrees, so that is not normal. I finally felt a little better, this evening, and went outside for the few minutes it took me to sand the blocks, but it has been cold out, so I didn’t stay long.

Ah, well, that’s life. I’m grateful to be back on the project again.

Thanks for looking.

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February 22, 2013July 13, 2013

Cello linings installed (front)

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Willow cello linings installed, glued and clamped.

Purpose of the collapsible cello mold:

My cello mold is built with a front and back “spacer”, each of which is removable to allow installation of linings. Each is held in place by a few drywall screws. I got tired of the repetitive motion of turning the screws by hand, and bought a very cheap electric screwdriver, barely sufficient for the task. I will later make a special attachment for it so that it can turn the tuning machines on double basses…that’s another task that wears out my wrists. Anyway– in less than two minutes I removed the front spacer, and the cello looked like this:

Cello mold with ribs installed, linings ready to install--front spacer removed. — Cello mold with front spacer removed and linings ready to install.

Dry-fitting the linings:

Then I cut the mortises into the blocks, fitted the linings (that I had bent earlier) into their respective places, and prepared for gluing. So, with the linings dry-fitted and ready for gluing, it looked like this (notice that only the center linings have clamps at this point; that is because they want to relax away from the rib, while the upper and lower linings straighten and tighten against the rib):

Willow cello linings dry-fitted, ready for gluing. — Cello linings (willow) installed dry, ready for gluing.

You can see the importance of the linings, by comparing the two photos above: without the linings, the ribs are only about 1.5mm thick…not very strong, nor is there sufficient gluing surface on that thin edge. So, with the linings in place the edge is about 5.5mm thick, which significantly strengthens the edge, and more than triples the gluing surface.

Hot Hide Glue and lots of clamps!

Once all the linings fit correctly, I heated up my glue, prepared a container of hot water, and my various brushes and palette knife, and, one by one, I brushed on the hot hide glue and clamped each lining in place. Those little spring clamps work pretty well. I got them from Home Depot, and they have served this purpose to my satisfaction. Occasionally there is a reluctant joint that needs more pressure, in which case I use a larger clamp, or one of those little f-clamps. (You can never have too many clamps!) After gluing and clamping, the cello looks like this:

Cello linings glued and clamped in place. — Cello linings glued and clamped.

Once these linings dry, I will remove the clamps and repeat the process on the back side. the back has a slight taper, from tail to neck. At the bottom block, the ribs are about 113mm tall. At the neck they are about 108mm tall. So I will want to plane the ribs to those approximate dimensions before I install the linings. One thing you can’t see in the photos is the fact that I fit the linings just a little high…slightly “proud” above the rib edge. I want to make sure that whatever planing needs to be done is primarily removing willow, not curly maple. I will accomplish final leveling with a sanding board, however, just before tracing the shape of the plates, from the shape of the completed rib garland.

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February 21, 2013January 10, 2014

Bent Willow Cello Linings

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Cello Linings, Willow, bent and ready to install

The linings I sawed up yesterday are now bent and ready to install.

While the bending iron was warming up (which takes about 20-30 minutes, especially in cold weather), I used a very small hand plane to smooth the edges of the linings, since some were still a little rough, especially if they had been the outside edge of the strips I cut from that beat-up 4 x 4 I brought home.

Once the iron was hot enough to make water droplets dance on its surface, I dampened each lining strip one at a time, and used a metal bending strap to force the wood against the hot surface of the (aluminum) “bending iron”. These linings are about 4mm thick, so I gave each segment a full 15 seconds to heat up, or 20 in the case of the c-bout linings which were to endure a tighter bend. As I heated one section, forced against the flattest curve of the iron, I counted seconds, then shifted the wood sideways to heat the next section, still maintaining the curve of the first, and so on, until the entire lining strip had the curve I wanted it to have. You can see that I deliberately over-bent them: I do so because it is pretty easy to straighten them out a little, to adjust them to fit tightly against the ribs.

Here is what they look like now:

Bent willow cello linings ready to install. — Bent willow linings, ready to install with hot hide glue.

Tomorrow evening, depending on how tired I am when I get home, (or probably Friday, since I have to go to bed very early Thursday in order to get up at 2:30 AM and go teach a code clinic class before my regular work begins on Friday morning) I will remove the front section of the mold (notice the screws holding it), which will allow room for the linings to be installed. I will cut the little mortises in each side of each block, to receive the ends of the linings, then brush hot hide glue onto each rib and lining, one set at a time, and clamp them in place with little spring clamps. After the front linings are dry, I will repeat the process with the back linings.

Starting to look more encouraging, now.

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