[pianotech] Damper tray block

[David Love]

As is typical, the reality is not as bad as the perception.  The blocks
turned out to be very slightly different dimensions but the placement of the
pivot hole was the same height from the key bed and the same distance from
back of the action cavity.  For those who haven't done this (which was me
until today) the procedure went something like this:

1.	Cut the new block using the old block as a pattern slightly shorter
than needed.  I made this one out of pinblock scrap (what would be do
without 	pinblock scrap) plies running front to back.
2.	Hold the old block and the new block back to back on a level surface
and index the screw hole for the new block which will be drilled from the
back 	of the new block. Insert a centering punch through the front side of
the original block and index where the screw hole will be drilled in the new
block.
3.	Set the new block in a cross vise and drill the screw hole from the
back of the block all the way through to the front.  Note: where the hold
comes 	through the front of the block is less important than where it
emerges from the back of the block, so drill from the back of the block.
4.	Flip the block over and use a forstner bit to recess the hole in the
front side of the block for the screw.
5.  	Screw the block into the action cavity at the old hole location.
6.  	Since you made the new block slightly shorter there will be a gap at
the top (most likely), but if there's a gap at the top and bottom that's ok.
7.	Note the thickness of the gap and cut a thin wedge of wood (or two
if there are gaps at the top and bottom) to be glued in place to take up the
slack.  
8.	With the new block screwed in place put some glue on the side of the
wedges that will contact the block (not the key bed or bottom of the belly
rail) and tap the wedge(s) lightly into place.  I found this easier than
trying to get the block perfect and the screw hole in exactly the right
place from the start. 
9.	When the glue sets remove the block, trim the wedge(s) that you
glued in place and you will have a perfect fit in the action cavity recess.

10.  	Measure the height of the pivot pin hole and distance from the back
of the block on the old block.  
11.  	Mark the new block by measurement and drill the hole for the
existing pivot pin.  
12.	Install and double check that the lever is spaced properly side to
side and that the underlever rests on the keyend felt at the same distance
from 	the end of the key at each end of the action.  If necessary you can
remove the new block and either shim or trim to move the tray in or out.
Also 	double check to be sure that the height is uniform from end to end.


Thanks for everyone's input.  

David Love
www.davidlovepianos.com