> Dale writes: > >>>To my mind it doesn't really >matter how . big the pin is, within reason a no.1 thru 4 pin as long >> as they render easily in the block. know what I mean. > > I think so. The fitting of the smaller diameter pin in the block is slightly less critical because of the smaller surface area. A a given PSI change in block fit will translate to a greater difference in feel at the lever handle with a large diameter pin than with a smaller diameter. Torque readings (and feel) will change less with humidity swings with the smaller pins. This is less noticeable in the low density blocks because there is more resilience to the material, so the friction gradient isn't as steep as in the high density blocks that don't compress as easily. At least that is the way I read it. I compute ratios of block fit PSI to torque readings at the end of a 10" lever at: 1/0 1.0 2/0 1.044 3/0 1.074 4/0 1.112 5/0 1.150 6/0 1.189 No, I don't have a way to measure PSI of the block fit at the pin. I judge them by feel like everyone else, but this is what the math shows, and it fits my observations through the years. > Given the amount of pitch change to be had without >moving the pin in a usual Baldwin block, there has to be a lot of give in >the system SOMEWHERE! There is both flex and torsion (twist). Most of the give in that Baldwin system is torsion in the very tight pins in the relentlessly unresilient block. Put those pins back in the vise and measure how far the end of the lever handle moves from pin twist between no load, and that ten pounds applied tangent to pin rotation. Then apply (by feel, and considerably more than ten pounds) the pull you would expect it to take to turn a Baldwin pin (up or down average) and measure that. A small diameter pin in a tight block will twist a long way at the top before the torque in the pin overcomes the static friction at the bottom of the pin. A large diameter pin doesn't twist as easily, so the bottom will move sooner. When the static friction between the pin and block is significantly higher than the sliding friction, both pins will snap in the block as they move, but the smaller diameter seems to snap less. My call. Ron N
This PTG archive page provided courtesy of Moy Piano Service, LLC