Action Ratio and Dip and Blow and Etc.

[Jon Page]

>Action Ratio:  5.7
>FW: 16.1g  (0.54 of Stanwood's maximum FW of 30.0g for note #40)
>KR: 5.2 DW: 50g UW: 32g BW: 41g SW: 9.1g F: 9.0g
>Knuckle-Core distance:  17 mm  Action Spread:  115 mm
>
>It appears all will regulate very nicely.
>I didn't measure blow and dip accurately at the time of this post.

Then you don't know if it will regulate nicely.  Set your key height, 
dip and blow to
see where the jack ends up at the end of the keystroke. Adjust your leverage to
have the jack end up in close proximity to the knuckle.

>Couple questions though. Action ratio is in the "normal" ballpark, 
>although perhaps not optimal for this action?

I didn't know there was an optimal ratio for a given action. The goal 
is to get it low
and still be able to regulate the action

>FW is way low for key #40, however, I have something in the range of 
>a "good" amount of lead - see picture below:

Low lead content means efficient action, that's a good thing.

>DW is nice - right where one would want it. UW is high - but is that 
>bad? Does the key ever return too fast for a pianist? But why is it 
>so high? I know that you don't get something for no price. Doesn't 
>that suggest that the action is suffering somewhere else?

UW is high because Friction is low, that's a good thing = fast repetition

>BW is high. So? As another person asked: What does BW mean to or do 
>to a pianist? What does it matter? What does it mean (I know the 
>definition) from a practical standpoint? David Love - what makes you 
>say that you like a 37g BW - is it because 37g BW "feels good" to 
>you - or that you can't "feel" BW, but rather when you have a BW of 
>37 the other parameters usually are near their optimum?

A comfortable range for BW is 38 to 42 with 38 on the light side and 
42 on the heavy.
S&S spec is around 35 for concert pianos (50/20). I usually shoot for 36 to 38

>It seems to me I am getting closer to where I want to be. Good 
>leading (key inertia), hammer weight and Down Weight. Seem like the 
>only thing concerning me is my high Up Weight and Balance Weight. 
>Are these a real concern? Why/how would the action perform better if 
>I were able to get BW down to 37g (or there abouts) and reduce UW to 
>25g or so - all, or course, without changing  leading, SW and DW? 
>Seems to me the only way to potentially do that would be changing 
>the action ratio - but how - capstan, wip rail, knuckle?

If your current configuration (with key height, dip and blow set) 
causes the jack to be
away from the knuckle then you have the option to move the stack back a few mm.
This will reduce the travel of the jack and reduce BW (and F,  maybe 
1 g). It will also
bring the capstan/cushion closer to the Magic Line, yet probably 
still too far behind.

The more efficient you make the action, the more transparent it 
becomes to the pianist.
A lower BW means less effort is needed to depress the keys.

>And I still have the nagging question about key lead on this action: 
>Why do I have such a very low FW, yet a "normal" amount of lead? 
>This also has me scratching my head and worrying that something is 
>horribly amiss elsewhere - again, the little bit I think I know 
>about action balancing is that everything is a compromise - you 
>don't get anything for free - the only way to pay Peter is to take 
>from Paul.

Low lead means efficient action, don';t worry about it...be happy about it.

>Man, when does it end?     :-0

Soon but it will start again with the next action.

-- 

Regards,

Jon Page
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