Joe,
On an already built piano, the basics of key height can be obtained by the case parts. With a normal white key dip, the bottom lip of the key covering should not touch the key slip. As you already discussed, the tops of the keys should not be pressing against the bottom of the open fallboard + its felt. Now, if you are establishing your own regulation specs on that keyboard and have changed any of the regulation, use your regulation as primary and fit the case parts to that. It's the way we did it in the factories. Get your key height the way you want it without the fallboard in place not straying
too far from what you initially measured. Same with the key dip and the keyslip. Your specs are already in the ballpark so this should work. You can fiddle with the key height, dip, hammer blow distance, after touch and so forth so the case parts as-is are very close and you get the optimum feel, power and sensitivity that you want.
If the keys show too much empty space under the fallboard, the most simple way to cure that is to glue a slightly thicker strip of felt onto the bottom of the fallboard. Conversely, if the keys press against the bottom of the open fallboard, it is simple to glue a thinner piece of felt onto the fallboard. If that is not possible, "remake" the fallboard bottom by clamping securely in the workbench and planing off a bit of the wood of the fallboard bottom, then re-felt it. When planing, keep the bottom in right angles to the front of the fallboard. This might also be of help to Larry who has that problem. Also be careful of any keyframe parts that reside under the fallboard such as studs for the key upstop rail.
The keyslip can also be lowered by removing the pins and planing down the bottom then replacing the pins. We're talking about only one or two swipes of the plane here. You don't want there to be visible space between the bottom of the white keys and the top of the keyslip. This is a little more complicated than the fallboard, but it can be done. Before planing, check to see that the existing keyslip bottom is straight across (if not, you'll have to duplicate its shape) and here also, keep the bottom in right angles to the front and back of the keyslip.
This way, you have your regulation and case parts just the way you want them. Oh, and don't worry about the little variations in Steinway specs. The way custom-built pianos are assembled, there are variation in plate height, bridge placement or even left-right placement of the plate that may necessitate fudging a bit on the regulation. The important thing is that the action operates at its maximum potential and sounds and looks good. It appears from your posts that these are your goals.
Good luck to you.
Joel
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Joel Rappaport
Rappaport's Piano Workshop
Round Rock TX
512-255-0440
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Original Message:
Sent: 06-29-2020 11:01
From: Joseph Burros
Subject: Fussing with Key Height on 1920's Steinway O
Hello Friends,
Due to my lack of experience with this issue, I am not sure what to do with a key height that is under spec on my 1920's Steinway O. I am wondering if I should increase the key height or leave it where it is. I own this piano, so I can fuss as much as I want with it. Right now the key height on Notes 1 & 88, measuring from the keybed (not the key slip ledge), is 2-15/32". This is below the printed Steinway spec, which is 2-5/8", or 2-20/32", so my key height is low by 5/32, which is an 1/8" plus 1/32". My understanding is that the Steinway spec is measured from the underside of the key top, down to the key bed.
The space availabe from the top of the key to the bottom of the open fallboard is 7/64", a little less than 1/8".
My questions are: Should I raise the key height? How much room do I have to raise the key height, if any, given the 7/64" space I have at the fallboard? And, will raising the key height about 1/32" or 3/64" make any different in regulation and performance of the piano?
What is your general opinion on key height to regulation, performance and tone? Do small differences in key height even matter? And is my example of off-spec key height typical of Steinway grands?
Thanks for your advice!
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Joe Burros
Cell: 646-410-7174
jbcello@gmail.com
www.fmi-newengland.com
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