[pianotech] high leverage action

[Gene Nelson]

>
>    -If you are going to increase your blow distance and keep the key
>    dip the same... or even (preferably) allow for a shallower key dip
>    setting if desirable, then you are going to have to increase
>    leverage.  (Which should be high enough already for that goal... but
>    set that aside for the moment)

**** Would not any increase in leverage require more key dip - such as 
moving to 17mm knuckle?

 A larger
>    knuckle, as Jon says, may also be a good idea if the ones you have
>    are small and/or worn.... didnt catch if you are using new shanks here.

*****  All action parts are new from Tokiwa. Knuckle diameter closely 
matches
           original parts and it was pointed out that this may not have been 
a good choice
          so I will experiment with this.

> This said... as both David and Jon echo, it looks like something isn't 
> quite right. You seem sure of your measurements so, the next thing to 
> check is your lines of centers. David mentioned this and I'd agree.  You 
> may have a geometry problem of some sort... Jon mentioned Bob Hohfs 
> article and the possibility of changing the stack height... the spread you 
> give seems reasonable, but you want to take a look at the jack angle at 
> the rest position and capstan / whippen cushion intersect with their line 
> of centers at half blow at least.

*****  I have learned the hard way that being sure of measurements takes 
considerable
           effort - I am in doubt once again so today I will be rechecking 
everything. The
           line that bisects whippen cushion/capstan intersection looks very 
good. Jack knuckle
           alignment could improve if the spread were reduced. The original 
whippen measured
           2mm longer from flange center to jack center as compared with the 
new Tokiwa whip.

> To answer your direct question.  It is my opinion that a blow distance of 
> 41 mm is a bit to low.  Gives you no room at all to change touch 
> characteristics... especially with deep key dip already, and it will limit 
> power more then I would want. What to do depends on whats causing the 
> inconsistency mentioned by all three of us.

**** Thank you for your explaination.

> Interesting side point.... this kind of reveals a major type flaw in the 
> idea of relying on simple distance ratio measurements to establish the 
> ratio. Jons initial guess (as I interpreted it) took for granted a low 
> ratio instead of the high ratio we are looking at.... tempting to do when 
> you just hear the key-dip /blow numbers.  Dale hopped on that with both 
> feet... and he's stated several times he just measures key movement for 
> hammer movement to get his action ratio.  Seems on the surface of it to 
> show what many of us have felt for a long time now.  Stanwoods approach to 
> measuring the ratio is a superior diagnostic tool for analyzing an action.

***** Agreed - I have used Stanwoods analytical tools as well as distance 
measurements.

Thanks so much for your advice - I have much to work on this weekend.

Gene