Adjusting wippen assist springs

David C. Stanwood stanwood@tiac.net
Thu, 11 Dec 2003 19:32:13 -0500


RicB writes:

>what, whats significant and whats not, a lot of it contested
>emphatically, and not much of any of it can really be shown to be known
>or adequately quantified one way or the other.

You can't argue the feelings of pianists and there are plenty who
emphatically like actions with properly applied support springs.  Pianists
feelings are an adequate quantity.

>But just so we are clear... many if not most assist spring actions these
>days are driving SW levels that are high enough to cause your wrists and
>fingers plenty of problems..... low key inertia or not. 

Most of the actions I've see that cause injury have ratios above 6.0 and SW
in the low high or even top medium zone and too much key lead.  As one who
has designed hundreds of assist spring actions I can say that most have SW
in the low to mid high zone which is not at all extreme with ratios in the
mid 5's.  As for actions with upper high zone SW, so long as the ratio is
close to 5.0 and the geometry is efficient, there is no pain or injury
there....

>they are not being used conciously to cover all ends as it were.
>Basically assist springs are still being used to overdrive the action.
>At least thats how it appears to me.

>Cheers
>RicB

I think it might be better said that most technicians think they can fix
actions which are already being overdriven by using wippen support springs.
 It doesn't work that easily.  You have to address SW and Ratio.
Any action can be made to feel great by balancing hammer weight, ratio,
Front Weight, geometry, and friction.  Springs are should be viewed as
extras for getting more performance out of the action.  I've certainly
noticed plenty of comments from pianist who notice that assist spring
actions repeat more surely than  non spring actions.

As a rule of thumb an assist spring action should play nicely even with the
springs disengaged otherwise the setup isn't right.

David Stanwood

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