[CAUT] CAF

[Mark Cramer]

I agree that the cushions are there for a purpose, and on one occasion where
they needed to be thinned, I actually had to shorten the regulating screws
as well (clicking), though these were still well below the shank-rest line.

All the same, I'm curious if our colleague (sorry I've dumped my deletes)
with the action with the CAF problems tried winking the jack to see if the
height regulating-button is bobbling (spring too weak to hold the lever
down)? 

If it's bobbling, adding cushion thickness might mask the problem, but it
sure as heck won't fix it.

I'd also be real curious as to how many of our suspected CAF causes could
actually pass the (2) jack tests and still fail to repeat? 

Mark Cramer,
Brandon University


-----Original Message-----
From: caut-bounces at ptg.org [mailto:caut-bounces at ptg.org] On Behalf Of
Richard Brekne
Sent: August 17, 2009 12:39 PM
To: caut at ptg.org
Subject: Re: [CAUT] CAF

Hi Fred.

Yes I understand this... and of course have run into it, and I agree 
that the degree the rest cushions act as a rebound for the shank is tied 
to the hardness of the blow. I just never really thought about how often 
the cushion actually serves this purpose. And I've not really considered 
it in a repetition speed context.  Most often when I see the shanks 
<<too high>> above the cushions its because they truly are too high and 
the hammer line simply needs to be dropped along with re-regulation of 
closely related parameters. This is one of the reasons I do not hold a 
10 mm key dip as a spec written in stone  as my good and respected 
friend André does.  I'd rather stick close to home on hammer blow 
distance and fudge more on key dip...and perhaps a tad on letoff to get 
an acceptable aftertouch.

Eric and I had a nice conversation at the Bergen Festival this year 
about a closely related subject.... finishing off the regulation he 
likes to fine touch letoff/drop by adjusting the jack rest position to 
get both actuated simultaneously.  I mentioned I liked to also float the 
rep lever height relative to the jack. Both are to a very small yet 
effective degree fudgeable.

Cheers
RicB

    Fred writes:

    ...There's the sympathetic buzz, but there is also a click on
    impact, if  a nut is "just loose." And it happens typically from mf
    up in  dynamics. Hence, the shank must be hitting the rail. I can't
    say I  have done detailed research (checking exact regulation
    parameters and  whatnot), but I have observed this very, very often,
    and with the  shanks set at normal distance from the felt on the
    rail. So it is  hitting the felt and compressing it enough to set
    the wood in motion.  BTW, I find that most individual cushions on
    wipps have at least  moderate indentations in the middle after years
    of play (especially in  the middle where they are played more). It
    isn't because the shanks were resting on them.