[pianotech] key leading documentation

[Joseph Garrett]

Paul said:
"If I were interested in studying key leading patterns in different pianos
by
taking pictures of certain keys, which keys would be the most
useful/representative? I find it easy to lay out all the Cs one below the
other, but this does not show the typical changes in numbers of leads
between sections, or where they occur. The difficulty I have found in
trying to capture the first and last key of each section is that photos of
black keys do not easily show the leads, which have been painted. Also, I'm
not sure comparing #26 sharp leading with #27 natural leading is the
best/most meaningful. Ideas? Does anything like this already exist
someplace?
 
Trying to learn about action ratios, inertia, etc. -- that is, from the
point of view of what's been done in the past, is common to certain makes,
models, periods of manufacture, etc. Thanks in advance for any suggestions."
 
Paul,
There are two ways that keys were leaded, imo. 1. a pattern was taken from
the prototype piano and was used on all of that model, regardless of the
considerations of friction, assembly line errors, different key material
masses and any other thing having to do with the actual function of a piano.
2. There have been a few factories that made the action correctly, in
regards to friction and action geometry, w/in the boundaries of mass
production, (albeit small quantities), and weighed off every set of keys
before the darn thing went in the crate.
I don't think any U.S. companies fell into #2.<G>
Studying what they did, really is of no concequence and is, imo, a waste of
your valuable time. Better to take John Rhodes/Darrell Fandrich class on
inertia. They'll answer all of the questions rattling around in your
punkin'.<G>
That's my take on that. 
Joe

Joe Garrett, R.P.T.
Captain of the Tool Police
Squares R I