Steinway Parts

[Michael Wathen 556-9565]

Ken Sloane's presentation at the Ohio State Seminar sounds interesting enough.
Too bad you can't bring the piano and the actions to the conference.  That would
really knock the sock's off them!

This reminds me that a while ago Ken had a presentation that appeared in The CUT
Newsletter on Knuckle configurations.  It was the spring board for some
interesting research which I soon hope to document and publish in the CUT
Newsletter.

My basic findings were:

      Steinway parts vary wildly.  Just because you purchased the parts from
Steinway and maybe they told you that they are the right parts for your Steinway
doesn't guarantee anything.  I have samples here that I keep in a little kit
with five different configurations.  Steinway will tell you "pre 1984" or is it
1988?, as if there were only two types of hammer shank assemblies ever made.
The most likely story is that these two types are the only two types available
from them.

      The knuckle configuration on a Steinway is the single most troublesome
part of refurbishing their action.  I found a constant coefficient that relates
the action arm distance ( the distance from the center pin to the point where
the surface of the jack intersects the roll of the knuckle) to the Downweight.
Something like a mm difference can account for as much as a five gram difference
in the weight.

      Examine any set of new Steinway shanks that have been installed to the
flange rail.  It is immediately evident that there are many which don't fall in
line and that the amount by which they deviate can be around the one mm mark.

      Conclusions:  Just because it says "Genuine Steinway Parts" don't think
you got it in the bag. The factory procedure of key leading and weigh off has as
its primary purpose to correct those mm inconsistencies that I noted above.
This means that if you replace the shanks then you have a new set of
inconsistencies most likely not in the same positions as the first.  This new
action can never feel as even as good as the original unless you weigh the keys
off and relead and delead as necessary.  Lot of work!!

In case your interested: I performed a linear regression with my samples
checking the the relationship of down weight to change in action arm distance.
>From this I was able to determine the slope and intercept that appears in the
formula below:

      Downweight = -5.972*d + 183.302.

The distance is in millimeters and the Downweight is in grams

For Example:

      If I measure an action arm distance of 21.4 mm then I can plug that into
the formula and I will get 55 grams. If I were to measure 22.4 mm instead then I
would get 50 grams for Downweight.

This was all done on a Steinway B.  The question is whether that will change if
I were to try the same thing on a piano with different leverage ratios (say,
Steinway D)?  I haven't thought about that before.  If someone wants to try to
answer this question, be my guest.  In the mean time I'll think about it.