Key dip

[Dave Nereson]

----- Original Message ----- 
From: "Clyde Hollinger" <cedel@supernet.com>
To: <pianotech@ptg.org>
Sent: Wednesday, November 05, 2003 6:14 PM
Subject: Key dip


> Friends,
> While tuning a 1980 Wurlitzer studio piano today I noticed some of the
> bass hammers would damp the strings depending on how they were played.
> Letoff was fine, but there was too much keydip, resulting in the
> backchecks pushing the hammers into the strings after letoff.
>     It appears to me that all other specs will be in the correct range if
> the keydip is reduced.  Can this be done by shimming up the front rail
> of the key frame, if there are no shims to remove from under the balance
> rail?  I've never tried this.  I could put card punchings under all the
> front felt punchings, I know.  Advice?
> 
> Regards, Clyde

    Yes, you can shim up the front rail.  Loosen the screws and insert the shims close to the screws.  If the keydip is fairly uniform already, it'll be a lot quicker than re-doing all the punchings.  If the balance rail punchings are already the thinnest felt available, there are no shims to remove, and the keys still need to sit lower, you can compress the punchings with a hammer on the top of the pinblock, if it's not a nicely finished surface and nobody's watching, or take handfuls of them to the front or back porch and pound them on the concrete.  But it's easier and more professional-like to either change to thinner punchings or level the keys where they're at and re-do the dip, either individually or by shimming the rail. 
    --David Nereson, RPT