[CAUT] FW: [Experts] erard action ratio and keydip

[Ken Zahringer]

Anybody have any ideas?

Ken Z.
-- 
Ken Zahringer, RPT
University of Missouri
School of Music

------ Forwarded Message
From: max di mario <maxdimario at alice.it>
Reply-To: <maxdimario at alice.it>, <experts at ptg.org>
Date: Sat, 7 Apr 2007 10:42:34 -0600 (MDT)
To: <experts at ptg.org>
Subject: [Experts] erard action ratio and keydip

I asked some questions regarding ideal hammer blow and key dip for an 1890
erard time ago and got some mixed responses.

upon studying the action I have come to the following observations..

when the hammers rest about 5mm from the bottom rail the hammer throw is
about 54-52 mm and in order to go through escapement properly the key dip
needs to be about 11 mm.

given the dimensions of the black keys and knowledge regarding 19th century
french pianos this key dip is way too big.. I believe..

if the key dip is reduced to 10mm key dip is about 48-50+ mm depending on
the section of the piano for proper escapement.

the knuckles are perfectly smooth.

if I put a key dip of 8.5-9 mm (which LOOKS correct regarding the dimensions
of the keys) the hammer blow becomes about 47 mm or little more than a
modern german-style piano.

so apart from the hammer-rest it looks like the hammer blow should be about
47-48 mm... BUT the hammers are suspended well over a cm above the hammer
rest..

so I have decided that the only sure-fire way to regulate the action
according to historical standards is to find the ORIGINAL key depth used by
the Erard factory in 1890...

does anyone out there know???

thanks.

MDM


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