[pianotech] Bobbling hammers and jack spring pressure?

[Jeff Cutler]

Paul, Jean-Luc, etc.
This winter the dealer that I work with has had several cases of bobbing
hammers, but mostly in the cheaper studio pianos.
I have found myself adjusting the let off button on many of these
instruments, and varying from 5-6 keys to an entire section.
This seems to do the trick in the store, but it may prove interesting when
these instruments have been in someone¹s home for
a season or two. Would addressing the issue by raising the keys be a better
solution? Or might that lead to leveling issues in a
year or so?

Thanks,
Jeff Cutler
cold & dry Minnesota


          Paul, 
> I jumped in when I saw that Gregor mentionned dry air. I'm not saying that all
> cases of boobling hammers are due to a drying and sinking kebed but I can
> testify, after working several years for a local dealer, that a lot of new
> Yamahas uprights would be fine upon arrival but start getting bobbling hammers
> after a couple of months on the floor. The only way to fix that problem was to
> raise the key height one way or another. I don't know whether it was the
> keybed, the punchings, the keys themselves, but the key height had become too
> low and the regulation was gone.
> Jean-Luc

Jeffrey Cutler
Piano Service
jeff at chordsandboards.com
651-398-6293




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