The case wood is quartered Alaska yellow cedar in the form of 3 boards 10 feet long, 7.5" wide and 3/16" thick. The latter two dimensions are final, as the boards were milled to my specifications when the original lumber I bought back in September was resawed. All I need to do now is cut the case pieces I need out of these long boards.
I'm starting with the bentside, which I've rough-cut to a length of 190 cm, about 4" more than necessary. Professional harpsichord makers usually miter all the corner joints when making Italian instruments, but frankly I'm too chicken to try this. My plan is to half-lap the joints, which, at each corner, will require one board to be glued on over-length and the mating board bevelled on its edge and glued up against it. Then the excess length on the first board will be cut off and the joint planed and sanded flush. This is slightly less elegant, I admit, but easier, considering that the bentside is a tricky item to deal with.
My bentside starts out as a straight piece of wood: it needs to be muscled into place against the curved side of the instrument and clamped. It's not pre-bent in any way.
Before gluing, I taped off all parts of the instrument that need to stay clear of glue, either for cosmetic reasons or because something else will later be glued to that area. Next, I attached some little blocks along the baseboard with double-sided tape, letting them stick out an inch or two past the edge. These will act as little shelves to keep the bottom of the bentside perfectly aligned with the baseboard edge.
The bentside, cheek and tail pieces are seen above, resting on the framework. Another detail to note is the block clamped to the wrestplank support at the rear left of the picture. This is to keep the part of the bentside above the liners from curling inwards, which I noticed it had a tendency to do during dry clamping runs.
Clamping the bentside is easy up above, since the clamps reach down to the liners, but clamping along the baseboard is difficult: the only way to do it with normal clamps would be to nail a bunch of angled blocks along the spine to help hold a long bar clamp. Instead I've chosen to pre-drill and countersink small holes at 2" intervals, through which I'll drive short #6 flat-headed screws. These will hold the bentside along its bottom, and later a decorative moulding will hide the screws from view.
With my father's help, we glued the bentside on in several steps. Before applying glue, we clamped the entire board on, though not with the full number of clamps we planned to use. Then we unclamped about half of the board at a time, spread glue along the baseboard edge, knees and liners, put the board back, clamped it, and screwed the bottom edge down.
A detail of the block supporting the bentside in the treble:
The treble part of the bentside has the most extreme curvature, and I found that simply clamping it along the liner would not bring the bottom edge in. I was leery of trying to force it into place with screws: the case wood is quartered, which makes it quite likely to split with rough handling. Instead, after one of my dry runs, I screwed four little blocks underneath the baseboard in the treble area, just back from the edge. Then, during glueup, we clamped a long stick to the case right in front of each block, letting it hang down a bit below baseboard level:
A C-clamp squeezed the stick and the little block together. This arrangement was able to bring the bentside bottom edge flush with the baseboard.
2 comments:
Your Work is very impressive. Gratulations for the progress you are making. One thing, although, I am wondering about: Why do you work with different kinds of wood than those used by Alessandro? His case and soundboard are made from cypress. I know, italian cypress is impossible to get in the required quality, but arizona cypress works very fine too and is available in North America.
Even I was able to find some good pieces of lumber here in Germany. As for the spruce soundboard I am aware, that Hubbard states, that spruce sounds better, but he also suggests a different way of ribbing than the one you chose.
In order to obtain the authentic sound of Trasuntino - wouldn't it have been more consequent to use cypress all over?
MB
Alaskan Yellow Cedar is a wood similar to Cypress. North American builders use it frequently as a very acceptable substitute for Med. Cypress which is all but unobtainable here.
Arizona Cypress is not commonly available anywhere in North America as lumber.
As for the choice of soundboard wood, Spruce was available. Med Cypress was not.
Overall, how one employs the materials at hand is far more important to the sound of the instrument than merely finding the "correct" species.
For a first build, I'd say this is going really well.
Post a Comment