Under lever gram resistance

[Horace Greeley]

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David,

At 09:02 PM 3/24/2005, you wrote:
>Actually, I'm talking about a new Renner underlever system.  The gram 
>levels start out around 25 grams at note 1 and graduate downward.  I take 
>these measurements with a gram gauge with the back action on the bench so 
>that I can adjust the spring tension.  The question remains, at what point 
>in the travel is the best place to take the reading.

Since the spring rate will change through travel from rest through stopping 
(either with the upstop rail or the end of the key movement), perhaps 
taking readings at several points through the travel of the underlever and 
then using an average would accomplish what you seem to be seeking.

>   Ideally, I want only enough tension to get decent shut off but not so 
> much that there is a noticeable difference between playing the piano with 
> the damper pedal engaged versus not engaged.  I don't like to notice that 
> I am lifting the damper with my finger too much.

Correct.

>  The next question is what is the minimum resistance that will still 
> produce decent shut off. I suppose it depends on the size of the piano 
> and the string mass, so for arguments sake let's say your normal 6 foot 
> Steinway.

There are at least a couple of other factors at work here.  The two that 
first come to mind is the length and spacing of the damper felt, which is 
often (especially since the mid-60's) poorly done in production and often 
simply copied later.  Wally used to teach a class in which this was 
discussed in detail.  I am presently out of town, and do not have access to 
those notes.  Perhaps someone else does.

Best.

Horace


>
>
>David Love
>davidlovepianos@comcast.net
>-----Original Message-----
>From: pianotech-bounces@ptg.org [mailto:pianotech-bounces@ptg.org] On 
>Behalf Of Joe Garrett
>Sent: Thursday, March 24, 2005 8:56 PM
>To: pianotech
>Subject: Under lever gram resistance
>
>
>
>When setting the gram resistance of on underlevers, what is the best
>point at which to take the measurement.  The higher you lift the lever,
>of course, the greater the resistance, so where in the travel should the
>reading be taken?
>
>David,
>  If you are trying to "gauge" the underlever when it is in the 
> piano.....NOT! Gram resistance should be taken on the flange, as with the 
> underlever out of the piano!
>The listed, (Steinway), resistances are: Lever Flange: 3-6, (I prefer 
>3-5); Top Flange: 1-3
>These numbers are from the OLDE Steinway Service Manual, so they pertain 
>to older Steinways. If the flanges you are checking are Teflon or Graphite 
>impregnated, then all bets are off.<G>
>Best RegardsJoe Garrett, R.P.T.
>Captain, Tool Police
>Squares R I

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