Dale and all, Dale wrote; > Stwy Models S ,M, L, O, All have plate horns with the screw >arrangement. Models A , B ,C ,D all have wedges. Wedges or horn they >do the same thing which is transfer load to the under beam assembly. > What I want to know is at what point you can keep the bloomin >thing from flying out of there as its strung. My best success is to >use a bit of pressure from a pry bar and block to give it a good >shove into position before the chipping and tuning is attempted. I have no doubt that, of the two arrangements you mention, the wedge shim is the superior design. When assembling rebuilt pianos, we routinely clamp the plate back against the pinblock prior to gently tapping the wedge into place. As Ron N. mentioned, a heavy grade of tape will to do the trick. Wim's mention of poor tuning stability without the wedge is something we have experienced also. We restrung a Yamaha C7F a couple of years ago which had no wedge since new. It's tuning stability markedly improved also, post restring with prior wedge insertion. The idea of clamping the plate back against the pin block would seem to be an appropriate assembly technique, and definitely so for pianos which have a non-bushed plate. Nonetheless, complications can still arise, especially when a representative from S&S is in a position to 'review' your work. During the 1996 dispute between S&S Hamburg and us, one of Steinway's 'complaints' was the position of the wedge in the allegedly inappropriately repaired D. Werner Husmann claimed in his report that the wedge was positioned too high (forcing the plate further back towards the pin block since the taper is arranged such that it is wider at the bottom). Now this claim struck me as rather surprising, more especially since the original pin block was retained in this instance. If the wedge was placed too high as claimed, since the pin block was original, would this tell us something about the way in which the plate and pin block was fitted originally at the factory? Indeed it would. While I admit that it would be possible also for a technician to drive the wedge in hard to a higher than appropriate position, by the year 1994 we were not 'Johnny come lately' grand piano rebuilders. We just tapped the wedge lightly into position. I have always believed that it is important that the plate, pinblock and case should be fitted together in such a way that there is no flex or stress between any two members prior to stringing. It would seem that the company was so 'eager to throw stones' that its technical representative (who should have known better since he was reputed to have been involved in piano design himself - Stephan Knupfer), apparently failed to think through the reasons why the wedge might have been positioned too high. Sure, if we had carelessly replaced the pin block, such a complaint might have had some justification, but since the pin block was original it could only point to one thing, the pin block was not properly fitted to the plate flange at the factory. I'm still waiting for an apology, following my comprehensive reply to the company, on this and many other matters in late 1996. Werner Husmann are you there? When assembling our own piano, we do not clamp the plate at all when fitting it into the case. Clamping is not appropriate in this instance since the plate has a two flange faces, one on each side of the pinblock. Firstly, the pinblock is closely fitted to the ground flange faces. then it is epoxy fitted to both plate flanges and screwed to the plate while the epoxy sets, all of which is done with the pin block out of the piano. The pin block is then is then fitted to the case with the plate and pin block still screwed together. The mating surface between the inner rim and each end of the pin block is checked for fit. If necessary (and it is almost always necessary), wooden spacer wedges are manufactured and fitted to each end, to set the angle and height of the pinblock to that required by the plate height and angle in the piano case. We believe that tuning stability is considerably enhanced by the epoxy fit between both sides of the pinblock and the plate flanges. Interestingly, we have found that the optimum drill size, when drilling double flange epoxy fitted pin blocks, will be larger than for conventionally assembled pianos. We believe this is due to the fitted flanges preventing pin block expansion as the pins are driven into the pin block. Where we might use a drill size which is 92-94% of the tuning pin diameter for a standard pin block, the double flange epoxy fitted blocks typically require a drill size of at least 96%. Ron O -- Overs Pianos Sydney Australia ________________________ Web site: http://www.overspianos.com.au Email: mailto:ron@overspianos.com.au ________________________
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