David said: "I have been tuning this piano since 1988 and the phenomenon has existed the whole time." Then, it would be logical to assume that the problem is somewhere else. Perhaps in the piano structure itself? I'd be checking the key bed construction and it's relationship with the plate and the case. Is it screwed on, (like many), or is it an integral part of the case? The Back Rail, is where the problem is, so I'd check that. What kind of Felt is used? Are there any shims in that area? What kind of wood? How is the grain oriented? How is the Action mounted? Is there a possibility that the Action mounts could be causing the problem? (perhaps not allowing the action to settle properly on re-insertion of the action.) Are the same keys doing this, or....is it different keys each time??? Also, I'd check to see if "flexing" of the key bed can cause the problem. Technique: sit at the piano and put knee under one end of the key bed...lift with knee. Do the same on the other end and the middle. Observe if anything happens.<G> "I replaced the capstan screws with thicker ones years ago thinking that this might solve the problem but it did not. Like you, I find it hard to think that the screws could turn in the wood; they are tight." I, too, find it hard to think that the screws are moving. I would suspect the mismatch of woods in the key end and possible expansion of the lead on the end of the key, which is almost directly under the "capstan screws"! Hmmmmmm? <G> Just my take on this conundrum.<G Joe Joe Garrett, R.P.T. Captain of the Tool Police Squares R I
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