Lost motion: (was puzzler on M & H BB

[Conrad Hoffsommer]

Ed,

, you wrote:

>>>Grand piano actions work wonderfully with no lost motion at all.
>>>If there is any lost motion, there will
>>>never be a straight hammer line as well as accelerated wear of the
>>>knuckle
>>>from the impact of the jack hitting it rather than pushing it to
>>>start.
>>>    We were taught at North Bennett to set the balancier so that we
>>>could
>>>feel the jack scraping, ever so slightly, across the leather of
>>>the knuckle when
>>>the hammer was at rest, and I have never had a problem with this
>>>causing loss
>>>of repetition.
>>>Regards,
>>>
>>>Ed Foote RPT


I agree with the method of setting the wink,('tis how I do it) however I 
have to disagree with the conclusion that there is no lost motion.

I believe that the scraping is felt as the _edge_ or corner of the jack 
rubs as it leave from under the knuckle. As it stands at rest, with the 
jacktop surface tangent to the knuckle curve, that there is a very small 
amount of a gap. That little gap (paper thin?) amounts to lost motion and 
is there for the same reason as that in an upright - to allow the jack to 
reset for the next stroke.

As you check the wink and trip the jack out from under, where does the 
hammer go? If it goes back to it's original position, what is holding it 
there? It can't be the jack! The only thing else under there is the 
balancier/repetition lever. If the spring isn't strong enough, it drops, 
doesn't it?

Just my 2¢...





Conrad Hoffsommer

All I ask is a chance to prove that money can't make me happy.