Cheek Lift & Rim Twist

[Delwin D Fandrich]

----- Original Message -----
From: "Joseph Garrett" <joegarrett@earthlink.net>
To: <pianotech@ptg.org>
Sent: September 24, 2001 9:14 AM
Subject: Cheek Lift


> Terry,
> Yes a traditional grand does get Cheek Lift. However, because the grand
> piano sits on 3 legs, you cannot check it as I earlier described. You can
> see it, if you have the affliction I have. And that is, when I go into a
> room, I immediately get a brain(?) signal if the room is not square or if
> the sheet rock is not flat. Bothers the hell out of me! Also, if pictures
> are not hung straight. I'm sure there is a way to measure a grand to see
if
> cheek lift exists. (Help me out here Del!) I have seen a few grands with
> that problem.


Joe & Terry,

I'm not sure I've encountered any like what you are calling 'cheek lift' in
so-called 'modern' grands. I have encountered quite a few with what I call
'rim twist.' I see rim twist the same way I see pictures not hung
straight--it glares out at me.

The easiest way for those of you who are not straight-and-square impaired
(as Joe and I seem to be) to see rim twist is to place a winding stick--an
old-fashioned name for a pair of straight wood bars used to check the square
of things like cabinets or boats or pianos...I use two pieces of carefully
machined pinblock stock each about 15 mm thick by 38 mm high by 1600 mm
long--across the front of the rim just above the stretcher and another
parallel to it across the back of the rim just above the bass bridge. Now
back up ten or twenty feet and sight across the tops of the two winding
sticks.

The front stick should be horizontal and parallel to the floor--assuming the
front legs are of equal length. It's the back one you want to pay attention
to. If there is any rim twist the right side of the back stick will usually
be some high giving the impression that the rim has twisted over the years.
At least this was my first thought when I discovered the phenomena. Now I'm
not so sure. We recently did two Steinway Model C's, one with a nearly
perfectly flat and square rim and the other with a good 15 to 20 mm of
counter-clockwise twist (going from the front to the back). I used to think
it was a characteristic of rims glued up in a single step as per S&S
practice but we're now doing a M&H Model BB--and you don't find rims (or
plates) much more massive or stronger than this--that has about 10 mm of
twist in the same direction.

I rather suspect that in most cases any rim twist present today has been
there since the pianos were new. (Keep in mind, I'm only talking about
pianos of 'modern' design here.) It probably got in there as the rims were
drying and/or being cut to height. I also rather suspect that other than to
offend my eye (and Joe's) it probably has little to do with piano
performance.

Del