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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
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Here are three hand planes that I use most often. The plane on top is a smoothing plane with a higher angle blade, fifty degrees, this helps reduce tearing on figured wood. The sole of this plane is corrugated which reduces suction on very smooth, planar surfaces. In the middle a little rabbeting, low angle block plane good for a lot of things, and good on end grain. The bottom plane is an inexpensive, old, but not antique, Stanley jack plane, that is re-sharpened with a convex curve in the iron, and with addition of small teeth. I use this plane for rough hogging or scrubbing of material. In the photo below you can see three soundboard panels in the drying room, the panel on the left shows the surface produced by this tool. Photo below, detail of the surface, the curvature of the iron allows more material to be removed at a pass, while the teeth minimize tear-out. This panel is in the first stage of thicknessing. The panel in the middle has its final thickness, and is rough s
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The planing sled, above, is a simple jig which allows uneven, or thin stock to be passed through the planer. In this case the work is shimmed up on one side so that a taper may be machined. Above, the planing sled and part passing through the machine. Below, the resultant taper. After some manual touch up the shelf is temporarily installed in the piano, at this point the piece fits snugly, which is far to tight as there will be a layer of Planetree veneer on both the top and bottom.
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Some stages in the making of the lower shelf of the pin-block stretcher assembly. Although I had originally intended to make this piece of the same construction as the original, I have been unable to obtain wood that satisfies me as to grain orientation. Above; a couple of five quarter, flat sawn German Beech planks, which in the lower photo have been re-sawn, and turned so that their radial faces are uppermost. Below; the six pieces glued together, the adhesive is Urea Formaldehyde, which is not reversible. This type of construction is more stable than the original, which, although being radially sawn, was very badly twisted in service. I can't help but feel that this was due to more than just the pull of the strings. The finished panel, jointed and planed up oversize. In its final incarnation this piece is tapered in longitudinal section, and tapered, bass to treble, in plan view. Below, the panel is planed to the major thickness, before tapering, and cut to the plan
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Although I have made quite a few sound-board panels using AR glue (see above) this will be my first using hide glue, so I'm going to approach it rather timidly, and joint and glue the panel one piece at a time. Otherwise, as I generally work alone, I would construct a heated table, if I were not too lazy, and proceed at leisure. The panel for the Erard has only seven pieces, the same as the original, so this method won't take very long.  Above, an intermediate step. The final two pieces, you can also join them in pairs, as shown below. The panel rough trimmed, and cleaned up, a bit, but not leveled, the thickness at this stage is around 10 mm. Final thickness will vary from 5.5 to 7 mm, before final thicknessing the panel will sit in the hot room for two weeks and shrink down. The hot room is set at 26% RH. In gluing up large panels out of individual boards, good woodworking practice usually dictates that heart wood should be joined to heart wood, and sap wood to sa
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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
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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 whet
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