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Expansion Crack in Piano Soundboard
By Robin P Clarke

[ Re: letter from Patrick Boeckstijns in 001007 MMDigest ]

> There is a crack in the soundboard.  Well, it's actually the opposite.
> There is no space, but it looks like the soundboard didn't crack
> because of shrinking, but because it has expanded (in top left corner)

Could be partly due to uneven wood or seasoning, and possibly high
humidity earlier in the instrument's life.  But such a "crack" is
certainly indicative of a reduction of the compression in the board
which is vital to the crown retention.  If it is of any length then it
could be significant.  Worth doing some sort of cut into it so as to
insert a shim at high force (as part of a recrowning method described
by DL Bullock).  Assuming you're restringing that is.

> I noticed most of the repetition springs have snapped.  When I touched
> a few testing them by pushing gently they simply broke where they are
> glued to the hammers.  I hope these parts are still available.

The springs attached (not glued) to the (string-side of the) hammers
(butts) are butt springs not rep springs.   But it's not clear quite
what sort of action you have here.

> The only reason the piano still could be played is when played loud
> enough the hammers just bounce back.

Which sounds like missing butt springs to me!

Robin P Clarke
Birmingham UK
www.zazz.org.uk



(Message sent Wed, 25 Oct 2000 21:19:33 +0100 , from time zone +0100.)

Key Words in Subject:  Crack, Expansion, Piano, Soundboard

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