Help with Upright Steinway Sostenuto

Israel Stein
Sun Aug 17 10:40 MDT 1997

At 05:32 PM 8/16/97 -0500, Vanderhoofven wrote:

Congratulations! Those upright sostenuti can be can be a monumental pain (I
hope there's a special circle in hell reserved for the designer/inventor,
who would have to spend eternity regulating them. Such trouble for such a
rarely used contraption!).

>Thank you for your help!  

You are very welcome - glad to have been of help.

>The DELRIN (not teflon) bushings were worn and

That indicates that at some point someone put too much pressure on them
(probably by overtightening the brackets). It shouldn't happen if all is as
it ought to be... The delrin bushing design does work - though it has very
small tolerances. Once you lose the factory setting, it's hard to
re-establish it (as I found out) - which is why replacing them with cloth
is so much easier, even if you do have to use trial-end-error to figure out
the right thickness cloth.

Now, you might still want to get those Steinway technical bulletins - on
the sostenuto regulation and some of the other topics they cover (I think
there's one on grand sostenuto, one on voicing for Steinway hammers - they
prefer the term "tone regulation" - and some more I don't remember). The
upright sostenuto bulletin also contains the procedure for regulating the
other type - neoprene tab - upright sostenuto, which is a bit more complex
than the cloth type. I think you can get them from Steinway Technical
Sevices - (Michael Mohr?)

Israel Stein, RPT

P.S. Don't worry about the length of your posts. If all they contain is
necessary detail (which yours do) that makes useful replies so much easier
to provide.