Several signs suggested to me, as I began to inspect and dismantle this nice-looking piano in figured walnut made about 1905 by the firm of Wilhelm Spaethe in Gera. I noticed that a lot of the short soldier wires on high beech blocks at the back of the keys were cranked to line up with the lever heels; the spoons on the levers were almost directly above the screw hole, making dismantling and assembly tiresome. I thought no more about it until I came to decide whether to fit new hammer-heads or have the existing hammers re-covered. Since my supplier had sent me a very nice set of Wurzen AA heads for another piano in error, I measured up and discovered that they would do pretty well for the Spaethe. It was then that I realized that the action rail had been wrongly drilled at the factory, so much so that the original finisher, in order to get the hammers in the central section to hit the strings, had not only stuck the shanks in at an angle but twisted the heads also, so that neither were the shanks vertical nor were the hammers hitting the strings at anything like a right angle.
The two pictures show how serious the error was. The butts have been rebored perfectly vertical and the hammers turned to meet the strings at a right angle. The error at the tenor break is about 13 mm. and at the treble break about 7 mm. Unless this were corrected, not only was it impossible to restore the piano responsibly but the mis-alignment of the parts would lead to both tonal and mechanical deficiencies.
The question was how to make a workmanlike and durable repair without losing all profit from the restoration. All the screw holes in the central section for the hammers, the levers and probably the dampers needed to be re-drilled.
Having checked that the strings ran perfectly straight from the middle wrestpin to the middle hitchpin and having drawn the strike line, I took a rubbing of the strike line for this section and made a mark on the left where the first hammer was striking thin air. Laying the rubbing against the screw holes, I was very glad to see that none of the new screw holes would overlap the old holes and only a few came close to them, so it would be possible to plug the old holes without any risk of weakening the hold of the screws in the new holes.
The first new hole was drilled in order to make sure the hammer would strike at a right-angle when the shank was perfectly vertical, and once this was verified, the marks from the strike line rubbing were roughly pencilled onto the rail and then marked lightly with the awl
To plug the holes I used bamboo sticks together with West System epoxy thickened with colloidal silica. The stick is first pushed into the hole and marked with the knife where it is flush with the face of the rail. The stick is then rolled under the blade of the knife but not cut right through, so that when it is pushed home in the hole it will break off flush and not need to be trimmed in situ. Enough epoxy is then worked into the hole to make sure that the hole will be completely solid with bamboo and epoxy.
Once all the holes are plugged, any excess of epoxy is wiped off thoroughly first with tow or scrim and then with a rag damped with spirit. Any plugs that are not perfectly flush can be given a tap or pushed in a little further with no difficulty
The screw line is next marked exactly with a spacer and chisel and decisive marks made with the awl to centre the drill.
Next the lever rail. This is plugged and a test drilling is first made, as before. More good news! It will almost certainly be possible to leave the dampers where they are and have been for 100 years. The brass spoons bend easily to touch the damper tail and moreover give easy access to the lever screw. Certainly it would be nice to move the damper bodies a little to the right, but there would be no real advantage.
The epoxy will now be allowed to set hard and then I shall drill the rail using the bow-drill. The bit I use for this sort of job is a nail ground to a point and then ground down to the diameter for about 20 mm. The holes also need to be slightly countersunk. The only dismantling necessary is the removal of the jack slap rail and this section of set-off rail, which will need to be redrilled also.
JD 3rd Feb 2008.