Jim Coleman, Sr. wrote: > .... > > I just hope that the graphite impregnated bushing cloth does not turn out > to be a problem in another 20 years. > > Jim Coleman, Sr. > > PS On the other hand maybe what we need in the piano business is planned > obsolescence just as they have in the automobile business. Do you suppose? --------------------------------------------------------- Jim, We do consider the graphite coated bushing cloth to be a problem today. We don't have to wait 20 years. We have had three problems with action parts using this bushing cloth. First, when we get parts bushed with this felt we find them to be quite erratic in friction. As well, between the characteristics of the bushing cloth and that of hornbeam, the centers are much more fragile than those we are used to from "the good old days." Second, when we finish any job we put our pianos on a playing in machine. This device strikes every note on the piano two times a second with about the same pressure as a pianist would use during normal play. We do this operation twice; once after rough regulation and again just before final regulation. The piano is played for two hours each time. We then check centers for friction and side play. All to often we find excessively loose hammershank flanges and excessively tight flanges -- sometime both on the same hammershank! -- after this operation. Repining them seem to be a fairly touchy operation. Third, graphite is somewhat hygroscopic. We find more of a friction variation in these action parts as the relative humidity changes. If I were given my "druthers," I'd prefer to have my action centers bushed with cloth using no lubricant at all. If something absolutely must be used, let it be McLube, which we find to be much more consistent and long-lived than anything else we've come across. Regards, Del
This PTG archive page provided courtesy of Moy Piano Service, LLC