> >Interestingly enough, it is the position of the Yamaha factory that wooden >flanges with felt bushings remain quite stable with regards to tightness >as (they say) the reactions of the wood holes, and felt bushings are very >close to exactly opposite to climatic changes. Indeed they argue against >Kawaiis (and others) use of plastic flanges very much on this basis. This is a common salesperson's story, but it is not borne out under actual testing. Feel free to try it some time. The wood hole does not enlarge evenly (it can become oval), and the change in the felt is many, many times more than the small change in the wood. Yamaha has a nice feature in their grand shanks which also stabilizes the bushing hole nicely by cross-laminating veneer on the shank forks. This makes the holes almost as stable as plastic :-) Only the surface fiber swelling will take place under humid conditions. Don Mannino RPT
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