Practical Action Geometry Question??

[Susan Kline]

I'll be interested in what the wiser heads have to say
about this, because I struggled with the same thing last
year, but since the piano is due for hammers in a couple
of years, I decided to try to make it work with the rails
as they are.

I ended up having to slice off some of the felt cushion
at the end of the jack window. Nasty, nasty ... had to
add a thin layer of bushing cloth to a few which then
started to click on hard blows. The action works, though,
more or less. But it's not "right". As you can tell,
my understanding of action geometry and how to change it
is still a work in progress -- well, that's the polite
way of putting it.

Oh, have fun, Brian! and do tell us what you decide to try.


Susan


><snip>
>The wippens are shorter in length by about 3mm,
>the variation appearing to be mostly out at the
>jack end of the wippen. When I leave the action
>spread at 4 1/2", as was the original, the jack
>doesn't have room to clear the knuckle before it
>burys itself in the felt stop at the end of the
>wippen.
>
>I can't seem to get a picture in my head of the
>negative effects of shortening the action spread,
>or if I'm doing anything wrong at all.  It's been
>drilled into us tech types that the action spread
>is sacred and NEVER to be messed with.  Well, I
>had to do something, 'cause the way it was, it
>wouldn't work, period.
>
>What has seemed to work in this instance is
>moving the hammer rail forward about 3mm.
>(Another possibility would have been redrilling
>the hammer rail to put the flanges a few mm
>farther back <towards the back of the keys>). I
>just wanted to run it past someone else who might
>have seen this stuff before just in case I'm
>overlooking a disaster looming on the horizon.
>
>Any insight?
>
>Thanks,
>
>Brian T.