Day 177: Deja Vu All Over Again

After the sizing episode, it was time to start gluing stuff to the soundboard. I started by lining out where the bridges and four foot end pins would go using a marking tool and punch.

Then, I threw some glue on the eight foot bridge and proceeded to get it down. I cut the heads off a few nails and used them as guides inserted into the existing holes. Once the go bars were in place, I removed the nails.

A word about go bars: This is an ancient method of clamping (or cramping for my friends in the United Kingdom) that probably goes back to the Egyptians, if not earlier. It simply uses the tensile strength of thin pieces of hardwood to bind whatever you're gluing to whatever is receiving it. In this case, it's all about pushing the bridges into the soundboard.

After 24 hours, I removed the go bars for inspection and all was well.

I then proceeded with the four footer, only there was a small hiccup - the damned thing snapped while I was bending it into position on the plan that was laid over the soundboard. Rather than become upset, I simply cut, bent, spokeshaved, and glued up a new one. All steps were completed within 48 hours. Easy peasy. So easy, in fact, I'm thinking about changing the company name to Tortuga Early Instruments Harpsichord Bridge Company.

Now that the bridges are in place, I need to cut out the sound hole (especially before I start gluing things to the back of the soundboard). I'm not going to disclose how I'm cutting it at this time, though I'll throw you a hint: Clean No Cars.

On a couple of tangentially related notes, I acquired a nice holly log from a woodworking friend. Thanks, Kate!

Like the PEEK from Robert Webster, I now have enough holly to make jack tongues for the rest of my days on the planet.

Another generous friend, Geir Bremnes, sent me drawings he has made of an I. Ruckers 1640 single manual that resides at the Rijksmuseum in Amsterdam. He's one of the kindest people I know and has asked me to pay it forward as a way to repay him for his generosity.

I'll be posting more about this instrument in the days ahead. Thanks again, Geir!

Until next time...

Day 176: Curling for Fun and Profit

Once I settled on the locations of the bridges on the soundboard, I could go ahead and make some more drastic measures to get things into place. For instance, the best way to position the bridges into the soundboard is to drill holes into them and nail them to, say, a piece of plywood under the soundboard.

As you may recall from my last post, I positioned the bridges according to their original locations on the R.K. Lee drawing of the 1640 as it currently sits in the Yale Collection of Musical Instruments. It was fairly nerve-wracking driving nails into my beautiful, pristine soundboard, but it was required, so there you go. And I did likewise with the 4' hitchpin rail, which will be mounted on the reverse.

More than anything, these become positional guides during glue-up, which will happen this weekend.

Another interesting aspect of soundboard preparation is the application of "sizing". Size is simply diluted glue. In this case, it's diluted glue made from animal protein in an 11:1 water to glue ratio. Sizing is typically used for later gluing because it will soak up and guide full-strength glue during a gluing session. In this case, it's intended to tighten up the soundboard, enhancing it's tonal qualities.

Now, the really interesting aspect of this exercise is the curling it produces on the incredibly thin (2-3mm) jointed piece. The top did not produce much curling (this is probably a photo from after it had settled down a bit).

The back was another matter entirely.

As I like to say, "Oh, boy." As nerve-wracking as driving nails into the precious thing was, watching it curl like this put my teeth on edge, so I stepped out of the shop for a couple of hours. When I returned, this is what I saw:

Whew. The little fella had settled down considerably and I could breath much, much easier. Of course, this is what Owen Daly said would happen. I trust him completely, but it was still interesting to observe.

Another aspect of the sounboard is the apparent discoloration. The photo of the top was taken while it was still pretty wet with the size. When it's dry, it maintains a consistent cream color. This was intentional. When I purchased the wood, it was in a stack of "piano wood" that had been sitting in a retail space for the better part of 15 years. This resulted in the outside of the wood darkening a bit. I purposely put the darker sides on the reverse. Once the soundboard receives the bridges and a little paint, all will be well.

Until next time...

Day 175: In the Green

After input from master builder, Owen Daly, and much research and deliberation, I believe I've come up with the proper placement trajectory for the bridges. This all began when Owen noticed something might be a little off with the placement of the bridges that would affect the ultimate tone of the instrument. In the absence of having specs on the original instrument this copy represents (the A. Ruckers 1640 single at the Yale Museum), I found string speaking lengths in "the O'Brien book" for an A. Ruckers 1637 single and recorded them (see table below).

Now, the instrument in Ernie's eBook Most Excellent represents a ravalement (later alteration) of the instrument, making it wider, which I believe would affect the placement of the bridges. Yet, I had a nagging suspicion I would want to stick with the original placements. This presented a secondary problem: I didn't have a drawing or any detailed information on the original instrument.

This is when Owen came to the rescue by loaning me his copy of the drawing done by R.K. Lee in 1971 of the original instrument at Yale.

This was a revelation. Based on the drawing, I created a spreadsheet comparing the 8' and 4' string speaking lengths (typically done for all Cs and Fs as a quick gauge) using all the data I had at that time. All measurements are in millimeters.

8’ Miller 1640 Yale 1637 AR* 4’ Miller 1640 Yale 1637 AR* c''' 171.5 169.5 171 c''' 89 80 83 f'' 257.5 259.5 258 f'' 132.5 126 129 c'' 331.3 345 348 c'' 174.5 169.5 173 f'  485.5 512 531 f'  253.5 245 258 c' 623.5 677 698 c' 332 324 338 f 884.5 927 963 f 450.5 450 474 c 1073 1111.5 1165 c 544 545 580 F 1320          1368 1351 F 695 697 717 C  1393.5          1409 1366 C 800.5 787.5 736 *Germanisches Nationalmuseum, Nuremberg, No. MIR 1073

As you can see, the figures in the tenor and at the hook vary a bit, yet all of the Yale 1640 figures are either very close or nearly the mean between Miller's copy and the 1637, especially with regard to the 8' numbers.

At this point, I marked out the 1637 and 1640 pins on the Miller plan. The orange marks represent the 1637 and the green represent the Yale 1640.

I now must make a decision: Do I follow the Yale green points or Mr. Miller's CAD drawing? Interestingly, when I laid the bridges onto the R.K. Lee drawing, they were a nearly perfect fit to the Yale 1640 marks with little final bending during glue-up required.

My inclination is to follow the green marks wherever they may lead. Regardless of my decision, the bridges will be glued down this week. Finally.

Until next time...