BSimon1234@AOL.COM wrote: > > I was wondering, however, why the piano companies did not anneal the original > rails. As you have shown, they easily could have, and I cannot imagine that > they did not know about it. I don't imagine that the manufacturers thought much about how the rails might work harden. It's such a unique application of the material. Do you think that over time, continuous impact > stresses from playing might bend the annealed tabs out of line? You are > gaining a ductility and losing hardness. Do you forsee any downside risk? This thought had occurred to me. Brass rails appear to have been stamped and so I expect that they start out partially work hardened. But my sense, having bent the tabs up and down with vicegrips, is that the annealed tongues are plenty strong enough to do the job and might even last longer than the originally made parts. I don't think that hard playing alone could bend the tabs out of line enough to deform them. Rather, I would be more suspicious of overzealous tightening of the butt plates being the culprit. The reason is because of the way they break. The groove near the end of the tongue is the weak spot and the ends of this horizontally-mounted double flange break downward, away from the pressure of the butt plate and in the opposite direction of the upward striking jack. The butt plates break at the fixing screw from the pressure of the screw. Note that on the piano I'm repairing, at least one of the _damper_ tabs was broken from "natural causes" (two more on the test section but I might have caused intentionally). Maybe the manufacturers should have published torque specs for tightening butt plates. The notion that piano technicians may be partly or wholly responsible for brass rail breakage only dawned on me as I wrote the above paragraph. I am moved to check if the action in my shop needs to have its screws _loosened_! Excuse me while I put the impact wrench away. Tom -- Thomas A. Cole, RPT Santa Cruz, CA mailto:tcole@cruzio.com
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