>Do you think there would be a problem if the tuning pin were also in contact >(being supported by) the steel face plate? Less so than in say, Steinways or Baldwins where there would be more distance between the coil and pinblock. At least that's my call. > I can see that the hole in the >steel face would need to be a greater diameter than the hole in the pinblock. Agreed. >If the pinblock hole is 0.020" undersize or so of the tuning pin, and the hole >in the face plate were drilled the same, then the faceplate and/or pin would >probably be damaged when driving it in. We didn't get a measurement on the steel thickness, did we? below a threshold thickness, driving a 0.082" pin into a hole of 0.020" interference fit would damage the pin, the steel layer, and most likely the pinblock. Above the threshold thickness (which shouldn't be that much), it just wouldn't be possible without destroying the pin. Maybe if the pin was inserted at something over 1200FPS... Actually, that's the sort of thing your FEM software should be able to graph pretty vividly, shouldn't it? >But what if the hole in the face >plate were 0.001 or 0.002 or so under the size of the pin? Do you think you >could drive the pin without damage? Much more likely, again, depending on the thickness of the steel. But the pinblock wouldn't supply much torque resistance. >Do you think that the steel would end up >supporting the pin? > >Phil F Support? Tension, yes, torque, no. The steel pretty much has to be counter bored for pin clearance if the thing's going to work. Ron N
This PTG archive page provided courtesy of Moy Piano Service, LLC