Lost motion: (was puzzler on M & H BB

[Mark Schecter]

Speaking of the springs, you might try cleaning and lubing the slot in 
the underside of the rep lever, and the curved loop at the end of the 
spring - if there's gunk under there, you could get intermittent hanging 
of the rep lever.

-Mark Schecter

Conrad Hoffsommer wrote:
> 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.
> 
> 
>