Before I can start to remove the pin-block, I would like to remove all the plate struts, except the center strut which is built into the stretcher. To do this I must cut apart the welded-in cross bars which are not original to this piano. In the photo above, the sound-board is protected with cardboard, and thin plywood before the bars are cut apart with a Sawzall. This is brutal work, and thankfully takes only a few minutes.


The plate struts are screwed into the piano. On the hitch-pin panel they rest on, and are screwed to steel stanchions (stand-offs). These small blocks of metal form the head of a bolt which passes through the hitch-pin panel and into the inner rim. In the front there is a similar arrangement, with small metal blocks, whose lower part forms a machine screw that passes through the shelf, and is secured from below with a round nut. Between these are a series of nose, or pillar bolts, that pierce the sound-board, and likewise through the strut, then being retained at the top by a slotted brass nut. These nuts were covered over by a recent type of resinous putty (Bondo) and were so badly damaged by a previous removal, that they had to be tapped out with a small punch. 

Above, the piano with all the struts removed.

Comments

Post a Comment

Popular posts from this blog

Image
I no longer joint sound-board panels with the machine, ultimately the hand plane does a better job. Unlike the hand plane, the machine Jointer produces a series of little scoops, the frequency of which depends on the feed rate of the work. A dull machine also tends to crush the wood cells, rather than cutting through them, which can cause a poor glue joint. At least one manufacturer of pianos is still jointing sound-board panels this way. In the first picture you can see the very simple jig, or shooting board, that I use for jointing thin boards. On some, more traditional shooting boards, there might be a wooden hook at one end to hold the work. My jig uses small C-clamps (see below). With the work clamped in place the board can be planed with the long, 24 inch, jointer plane. This keeps the edge square, and saves the worker the trouble of balancing the plane on the thin edge of the board, were it clamped vertically.  How force is applied to the hand plane, determines ...
Read more
Image
As I will be gluing the sound-board together in this next step, it seems an appropriate place to stop and talk a little bit about glue. Many restorers and conservators talk very negatively, and vehemently so, about AR, or Aliphatic Resin, glues. One major complaint about this type of glue is that it creeps, and that joints under constant stress will eventually fail. In thirty years of cabinet making, over ninety modern sound-boards, and two new modern instruments, one weighing over 2000 lbs., I have yet to see a single joint fail as a result of creep, although I am well aware that there are others who do not share this experience. In every case where I have replaced a modern sound-board, the original board failed as the result of the use of animal glues. One other often cited problem is that joints made with AR glues are not invisible. Let me assure you, that properly constructed joints assembled with AR glue, are as invisible as they would be with any other adhesive. Having said ...
Read more
Image
Here is a picture of the ribs roughed out, the central spine consists of two pieces (Spruce) that will later be steam bent, and glued, the top bridge is made in a similar fashion. A modern multi laminate bridge can be made cold, and will hold its shape, but with only two laminations, there would be a large amount of spring-back. Below the steaming/laminating form takes shape out of layers of plywood, one side is a single piece attached to a stationary base, the remaining being individual movable blocks. The offset between the blocks is 30 mm, which is the width of the bridge before final shaping. Above the sides of the steam box before assembly, the box is eight feet long, by about six by six inches, just large enough to accommodate the long thin strips of the bridge and spine. Below; the box assembled. The parts to be bent are suspended on a row of half inch Maple dowels that span the interior of the box allowing the steam to penetrate from all sides. Steam comes from a ...
Read more