Backcheck height

[Avery Todd]

Hi Ed,

Some good suggestions. But I still think the basic problem is that the
backchecks are installed too high. At let-off, the tails are significantly
below the tops of the backchecks. But your suggestions could solve the
problems until I can get the real problem corrected. Thanks.

Avery

At 08:11 PM 05/27/03 -0400, you wrote:
>Avery writes:
> >newest D. I don't know if it was done that way at the factory or at the
> >dealer but the backcheck height is appreciably too high. I've had "clunking"
> >noises from the hammer shoulder rebounding on it; notes failing to repeat
> >in a very fast repetitive "situation" (had complaints about it), because the
> >shoulder was getting hung up on the backcheck
>
>   Greetings,
>     I have seen this problem before, also.  The fix?  a sharp knife!  The
>very lowest portion of those hammers are probably solidified with lacquer, 
>and if
>not, you can go ahead and soak them sufficiently to keep the felt from moving
>around.  Then, take a utility knife and carve as much felt out of the way for
>clearance.  It won't take off enough to worry about weight changes,(given the
>surrealistically erratic SW found on factory hammers), and the hammer
>integrity won't suffer if there is a solid matrix of felt and lacquer down 
>there.
>
>
> >(I couldn't make the hammer
> >check high enough because the checks were too high), plus what has  already
> >been mentioned about the tails rubbing on the backchecks.
> >>I'm going to replace the backchecks and wires and set them so that the 
> tail
>at letoff
> >is app. 2 mm. above the backcheck, assuming the hammer bore distance is
>correct,
> >of course. :-)
>
>    Often, when there are tails rubbing leather, (mmm, sounds like a x-rated
>cowboy movie) and hammers bouncing off the checks, I have found that the
>inter-relationship of back-check angle and tail shape are the root 
>problem.  I would
>suggest that you take a few of the hammers and shanks off, and with a
>divider, check to see if the curve of the tail matches a radius of 2 
>9/16".  If not,
>then see if there is enough wood left to allow you to re-carve them to this
>radius. Sometimes the factory hammers are shaped with a significantly smaller
>radius and the tails drag at about their middle.
>    Once done, see that at rest the backcheck is leaning distally slightly
>beyond a 90 degree angle to the shank.  This is a good starting 
>point.  Assuming
>a proper keydip, you should be able to get the hammers to check no more than
>1/2" from the strings with no bouncing off.
>Let us know what happens,
>Regards,
>
>Ed Foote RPT
>www.uk-piano.org/edfoote/
>www.uk-piano.org/edfoote/well_tempered_piano.html
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