replacing a Bluthner action

[Richard Brekne]

Avery Todd wrote:

> I thought Richard did "something" along the lines of a magnetic action.
> Am I wrong?
>
> Avery

I have a full blown origional solution to magnetic assist actions, which 
employs a pair of opposing magnets on the key stick and whippen forward 
of the capstan, and a pair of attracting behind the capstan.  This is 
different then most other assist systems in that it pits one moveing 
lever against another instead of a non-moving point against one of the 
levers.  The whole system is described in an article published both in 
the American and European journals last year for those interested.

That said,  the exact same concerns I have stated here were underlined 
in that article. Assist systems should not be used to avoid dealing with 
designing into an action desirable mass levels.... i.e. inertial 
characteristics... i.e. dynamic touchweight.  Flip side of that 
postulation is that once these are designed in, the only real need for 
any assist mechansisms would be to compensate for very small variances 
in action ratio that are unavoidble in building any action.  
Essentially, this means around 1-2 grams dead DW max, unless one is 
designing purposefully an action which will be used to replace a 
predetermined amount of counterbalance mass. To my knowledge, no one yet 
has done any real research into the resulting dynamics of such an 
action. That fact, combined with the more generalilzed fact that 
pianists playing concert intruments around the world have clearly 
demonstrated a preference for non assisted actions... leads me to 
believe replacing counterbalance mass with assist springs is not such  a 
good idea... at least not as has been employed by any manufacturer up to 
the present. So I conclude for the time being that any assist mechanism 
should only be used to even out very small variances in static DW.  One 
could argue that it would be better to find the root cause of such 
variances (ratio problems key to key) and solve those instead.

fwiw... I have refined the whole concept employing a new twist on the 
old rocker arm capstan to eliminate the problem of the magnet pair 
getting in the way of capstan adjustments.

Cheers
RicB