The new soundboard

is almost done. I changed up the order of work this time. Previously I thinned the entire piece of joined boards, then cut it to size. This time I cut it to rough size, then thinned it. Faster and more precise. Also, I used a belt sander this time to quickly thin the thing from about 0.200" to <0.013". Planing last time took several whole days; the sander took several hours. Joints are nice, still.

Soundboard, take two

I ordered a new batch of wood from Switzerland to make the soundboard anew. The last one wasn't quite perfect. This one I'm being super careful on, especially in terms of the glue joints.

Thanks to Mr. R. K. Lee (who drew the plans up), I learned that I need to let the dry glue soak up the water for an hour before melting it. Makes it much easier to spread on the joints quickly. The odd joints are glued and clamped (except for the one longest one; I ran out of clamps), shown in the picture in all 52 clamps.

Hmm

So the odd angles I mentioned previously are because the instrument warped since it was built 300 years ago, and the plans show the instrument exactly as it is. I'm trying to figure out what to do now... the jackrail and upper and lower belly rails are the only things that are at odd angles.

I'm going to add a tapered (wedge-shaped) panel to the keyboard-side of the lower belly rail so it becomes perpendicular. I squared up the jackrail easily by moving the notch in which it sits. The upper belly rail doesn't go in mechanically (just with glue), so I can move that square easily. [Update: April 27]

Looking Like a Harpsichord

Since yesterday: roughly trimmed the end of the soundboard, adjusted the wrestplank support blocks and added the jackrail.

Jackrail info: (this is the piece that spans the narrow dimension, at the wide end of the soundboard) Made from a 1" thick strip of poplar, with a routed molding and a 5/8" by 2.75" wide dado. The jacks (things that pluck the strings) hit this and then fall back down.

The angles in this thing will be the end of me: the jackrail is at an 89 degree angle from the spine, which is significant enough along the 33" width that I had to match it...

The Case Nearly Done!

Look-ee! All the parts are there: the soundboard, the 4' hitchpin rail (hidden under the board), the 8' bridge, the 4' bridge, the wrestplank and it support blocks, the 4' nut, the rose, the upper belly rail... etc.

Remaking: the rose and the 4' nut.

Need to make: the 8' nut.

Tomorrow: will attempt to bathe the whale again (a.k.a. damp the soundboard to swell it to 11% moisture content) so I can glue the soundboard bars and bridges.

Fitting the Soundboard

I began fitting the soundboard to the rim, now that the liner and upper framework is done. First I roughed it out with a hand saw, then used a block plane and spoke shave to fit it exactly. The soundboard must fight tightly into the case.

A note on moisture content: The soundboard needs to be installed in the case while it is dry so that in the summer (humid) it crowns up. It would split and crack if that was reversed. The soundboard was at six percent moisture content from sitting in the shop. It should be fitted to the case at around percent (says Zuckerman/ZHI). So I sponged it down on one side and thought the moisture would penetrate given the thinness, but I returned after letting it sit for three hours and found it had buckled up so that the center was about eight inches higher than the edges.

More later, off to work on it now.

The Upper Frame

I made the five upper frame members (fir) and glued them in to place. The design of these is pretty weird: they are about 2 inches tall, but because of the 4' hitchpin rail (glued to the underside of the soundboard; shown in the pic: the curved piece in the middle), they have large cuts in them to make space. That's understandable. The weird part is that only about 1 inch of them actually comes in contact with the side of the case, by way of the liner. The bottom half just floats. There's not much gluing surface to work with.

On Monday I get to make the little wedges that help anchor these frame members against the side of the case. Unfortunately, each of these wedges (of which there are about 20) is a different dimension, with unusual angles...

Gluing the Liner

The soundboard rests on a ring of wood strips inside the case called the liner. Here it is being glued.

Bridges, Nuts and the Wrestplank

I managed to drop my phone in a mud puddle around Thanksgiving last year, and since doing that I haven't been able to get the USB connection to work to upload photos. I just got a Bluetooth dongle today that works for file transfer, so here's the update from the past three months:

I've finished shaping both bridges and one of the nuts. The bridges are satisfactory, but the one nut that is completed is too wavy for my liking, so I will be remaking it soon. (That nut is shown at right.)

I made the wrestplank. It is made of three pieces of poplar joined together, laminated to two pieces of poplar with the grain going the other direction, veneered with soundboard spruce. The tuning pins go in the wrestplank, thus the many holes. (The hole positions were very accurately transferred from the drawings.) See pictures.



I finished making the soundboard bars (these reinforce the soundboard from the underside).

I cleaned up the case, cutting of the overhanging dovetails at the joints and grinding them smooth with a Festool sander-grinder (very cool tool).

I cut the molding into the case. I started out trying to make an authentic molding as follows: I cut a molding scraper in steel using a water jet (pictured) and attempted to scrape away the design into the whole case rim. This was taking forever, so I tried removing as much material as I could with a finish router. Still, took a long time. Then I figured that I'll be the only one who will care if the molding isn't authentic, so I just used an S-curve router bit. (It would have cost $50 to have a router bit custom made, which wasn't prohibitively expensive, but the difference was small.) I have to carve several inches of the molding near the joints, because the router can't get in to those areas.

I need to get the soundboard in this winter, otherwise I will have to wait until the next one. If the soundboard is installed during the winter, it will crown during the summers. If, on the other hand, the soundboard is installed during the summer, it will crack during the winters when it shrinks. The crowning is much preferred. I should be able to get the thing installed next week.

Peace-

Unison Bridge... part 1

There are two bars that go across the soundboard that the strings are stretched over (one bar is called the bridge, the other is the nut).

In the pictures here you can see the beginning of the bridge. So far it's sawn out to rough size and shape... now I need to shape it to the exact dimensions with a spoke shave.

The plans for the instrument provide measurements for four cross sections of the bridge, down to the 1/100th of an inch. This is a critical part of the instrument because errors in the dimensions could cause the strings to buzz, and it also affects the scale quality.

(In the picture, everything is upside down, but you can get an idea for where things go.)

American Woodworker

There's a good article about my project in this month's American Woodworker, in conjunction with a great story on the hobby shop!


Go grab a copy! :)

And thanks to the folks at American Woodworker!

Milling the Rose; Milling the Bridges

Almost all the remaining wood I need arrived from Hearne Hardwoods this week. I got some massive boards... e.g. a 24" wide piece of European beech that weighs over 100 lbs (in image). I also got a really nice piece of Gaboon ebony for the key veneer.

The beech for the bridges came 2" thick; the bridges are only 0.5" thick on average. I started milling down the planks to rough size today, cutting a chunk out of the big beech plank and flattening a face on the joiner.

Today I also milled down the rose from before. I reduced the thickness of it to less than 1/8" by sweeping the back of it with the mill. I also used an indexing head to clean up the punched pattern around the rim, and cut off the excess material.

Soundboard, part III

Planing to thickness
The resawn boards were about 1/4 to 5/16 inch thick. They need to be 9/100ths of an inch thick. I was afraid to use the thickness planer to go less than 3/16ths of an inch thick; beyond that, it is all hand planing.

The piece show in the picture at right is to the correct thickness for now (1/10th of an inch). I have four more boards to plane, and then a small amount to remove with a sander.

Soundboard, part II

Joining
For the past four days, I've been gluing the boards together with hot ground hide glue. This glue, as the name implies, melts around 150 degrees F and gels within five minutes. It cures very hard and resonates with the wood. It is the same kind of glue that was used in the original instrument.

The Soundboard, alla New Yankee Workshop

Resawing
The boards from Switzerland came about twice the thickness I needed. My first step was resawing the wood (cutting it down its length) into half-thickness pieces. This was done on the bandsaw with a fresh blade and a point fence. (The piece of wood in the picture was a scrap that I tested the fence setup with.)

Wood!

Just got the soundboard wood from Switzerland today. (Quite a fun time getting it here: shipping was about $400, plus duty; and had to clear the wood through customs at the airport.) But it's here, and it sounds super nice when you tap on it. It's the same wood that Stradivarius used to make his violins. It's harvested by a small company in the mountains after the full moon, around midnight, then flown down the mountain by helicopter and quartersawn and air dried.

Making the Rose: Wax Carving

Here's a pic of the new rose wax positive...

Leg Carving 1B

I decided I'm most likely going to replace the first leg I carved for a few reasons: 1. I didn't rough it out finely enough, so the edges are too wavy; 2. I made it too deep, so the bases of the raised elements stand out and are ugly; 3. overall I'm more used to the tools and think I can do a better job.

In just three hours today, I got as far as these pictures show. Notice the band along the edge is a totally consistent width. The carving isn't nearly as deep (though I really can't decide if I like the carving deep or shallow). Most of the speed came from roughing out the shapes with a high-speed cutting bit on my Dremel tool. If I can get to the point where I finish a leg every five days, I'll be quite happy.

I still can't quite get the organic look to the carving that the original had :(. It's getting better though.

Please take a look at the first leg a few posts down. I'd like to know other people's opinions!

Straight from the Mold

Here's the rose out of the mold. I now need to cut off the excess, thin the back (it's about 1 cm thick and only needs to be 5 mm) and file some edges so they're smoother.

(sorry... I'm too lazy at the moment to get my real camera out)

Edit 27-July: I decided I'm going to remake the rose, since it was fast. This time I'll tint the wax so I can actually see what I'm carving.

Casting the Rose

In the soundboard there is a 3" hole with a metal "rose" (medallion-like thing) in it. To make this, I poured a disk of wax, carved a positive rose, cast plaster around it, baked the mold, melted the wax out of the plaster, then melted a mix of lead and tin and poured it into the mold. (Actually... I'm not 100% positive what the metal is. I used plumber's bar solder, and it had the "this product contains chemicals known to the state of California to cause cancer..." warning on it, so it really could be any mix of lead, tin, silver, antimony and copper. I was hoping to find 50-50 lead-tin.)

I haven't broken the mold off yet, as the metal is still hardening. But here are pics of the casting!