Bosendorfer hammers

[MMiccio@aol.com]

Hi Newton and other interesed parties,
Thanks for your suggestions so far,  here's a recap: a 20 yr old Bosendorfer
model 225 that has string height of 207-214mm (#1-#23), and 207-210mm
(#24-#92) and a hammer centerpin height of 150mm, the factory spec says it
should be about 208mm in the bass and 201mm in the treble sections and the
recommended hammer bore is 52mm in the bass and 48 mm in the treble. Doing the
math, the bass requires a hammer bore of 57-64mm (#1-23) and 57-60mm (#24-92).
I think the makers must have installed a pinblock thicker than their regular
block to have measurements this different from factory spec. (This piano has
not been rebuilt.)

Here's where I'm at.  I just went back to the piano yesterday to try
regulating a few sample notes with some mocked-up hammers to simulate the
required hammer bore and it seemed to regulate ok. I taped "stuff" to the tips
of a few of the existing hammers to make them as long as needed.  I had to
lower the hammer rest rail quite a bit but there was ample space.  The letoff
rail should be shimmed down so I don't have to unscrew the buttons too much (
1-1/2 turns is required and they become pretty loose).  Drop screws were near
maximum height already so these will end up being somewhere in the middle of
their range.  Back checks need to be moved back and may only have to have
their lowest back edge trimmed to insure clearance with the sostenuto rail
(although the longer hammer bore means I have to pull the keyframe towards the
keyslip to maintain the same strike point, which helps with the backcheck
clearance.  There is room at the keyslip.)  The hammer tails which are 1" long
contact the backcheck pretty low, I imagine I can have the tails shortened to
around 3/4" ( which will also help with backcheck/sostenuto clearance). I
could only approximate whether or not there is a straight line from Whippen CP
to Balance point on the key but it seems to be ok when I lower capstans for
the longer hammers.  As you may recall my main concern is weight increase with
the longer moulding. I am hoping that some additional hammer tapering  will
help there, perhaps as someone mentioned, a "lightweight" moulding from Renner
and jacking up the Aux repetition spring (which goes only to #64) also.
What do you think, am I missing something that should be considered here, can
I have hammers bored with the range I need, directly from Renner USA.? 

Mike Miccio, RPT Brooklyn NY