[pianotech] wooden click at letoff?...reprise

[Jim Ialeggio]

David S(no C) wrote:

<While you don't seem to have swapped out the reps themselves, you 
appear to have focused in on the damper mechanism as a variable. (I 
wrote the following before re-reading your post re: dampers, but thought 
it worth mentioning: Did you notice whether the jacks were centered in 
the rep slot? or whether the pinning of the jacks was firm? Off-center 
jack can either contact wood or glue (jack stop felt).

David... jacks are centered reasonably and there is no wood on wood 
contact in the range of jack motion. I did not remove the spring from 
the jack to test the pinning, but did bring the A0 whip home to match 
and try and swap out for 2 new reps next time. I attempted to swap a rep 
on-site, but would have had to remove travel paper from the 
non-symptomatic rep to do the swap. Time was running short, so taking a 
sample whip home seemed to make the most sense to pull off the swap.

I did start focusing on the damper mechanism because the noise 
disappeared after depressing the sustain pedal, but I also wrote that I 
was skeptical that the dampers were the problem...I'm exploring them 
though, and not eliminating anything as the culprit.

<Zeno's point, re: damper stop rail felt is good, however, that would 
seem immediately evident when testing individual damper lift.

Right...the sound is not obvious when the damper lever is run beyond its 
normal range of movement. At least I thought I was taking it beyond its 
normal range of movement. I will check to confirm this next time, as 
well as check John P's sostenuto point.

<Wim's observation also good. Did you check for any glue or hardness on 
the key-end felt?

Yes. And scraped the felt gently to expose a fresh surface...still not 
it. Also scraped the drop screw contact leather to expose fresh leather.

I noticed that the existing knuckle ecsaine was not as taught to the 
knuckle under felt as I thought it should be. When pinched, the ecsaine 
lifts from the underfelt. I thought this was not ideal in such an 
important interface. I checked out the new Renner shanks I had with me, 
and their ecsaine, when pinched was as migratory if not more migratory 
than the old, so I didn't bother switching a new knuckle for an old.

The looseness of the knuckle ecsaine/underfelt piqued my curiosity. So I 
checked new WNG and Abel knukles I had in the shop. The 
ecsaine/underfelt did not deform as easily as the Renner, and on both 
the WNG and Abel I was not able to pinch the ecsaine away from the 
underfelt, with the WNG being the tightest knuckle wrap. This tight wrap 
seems like good, if not essential, idea to me in this important spot.

So, regarding loose damper lever leads...what are the symptoms? I've not 
run into this before.

Jim Ialeggio




-- 
Jim Ialeggio	
jim at grandpianosolutions.com
978 425-9026
Shirley Center, MA