 |
Welcome to the Piano World Piano Forums
Over 3 million posts about pianos, digital pianos, and all types of keyboard instruments.
Over 100,000 members from around the world.
Join the World's Largest Community of Piano Lovers
(it's free)
It's Fun to Play the Piano ... Please Pass It On!
|
|
|
|
73 members (Carey, 20/20 Vision, AlkansBookcase, bcalvanese, 36251, brdwyguy, amc252, akse0435, 13 invisible),
2,110
guests, and
299
robots. |
|
Key:
Admin,
Global Mod,
Mod
|
|
|
|
Joined: Dec 2012
Posts: 6,714
6000 Post Club Member
|
OP
6000 Post Club Member
Joined: Dec 2012
Posts: 6,714 |
I was thinking about what is actually vibrating when we hear the little "squeak" that knuckles sometimes make.
Is it the wood of the repetition lever? Or is it the buckskin/ecsaine?
In a seemingly infinite universe-infinite human creativity is-seemingly possible.
According to NASA, 93% of the earth like planets possible in the known universe have yet to be formed.
Contact: toneman1@me.com
|
|
|
|
|
Joined: Apr 2007
Posts: 3,332
3000 Post Club Member
|
|
3000 Post Club Member
Joined: Apr 2007
Posts: 3,332 |
Interesting question Ed! I never thought of it before. I think it must be the wood, as I can imagine it heaving a resonate frequency of some kind, unlike the knuckle which seems naturally damped.
But I think it would be the jack itself as opposed to the rep lever, since the squeak happens at when the jack starts to rotate.
|
|
|
|
|
Joined: May 2012
Posts: 294
Full Member
|
|
Full Member
Joined: May 2012
Posts: 294 |
I'm thinking the leather of the roller is causing the jack to vibrate, in the same way as a violin bow on strings.
Started work at the Blüthner piano re-building workshop in Perivale, UK, in 1989. Self employed since 2000. Learning something new about pianos every day...  #hamiltonpianos http://www.hamiltonpianos.com/
|
|
|
|
|
Joined: Feb 2011
Posts: 4,331
4000 Post Club Member
|
|
4000 Post Club Member
Joined: Feb 2011
Posts: 4,331 |
Passing thought, leather can squeak when polishing a car. PS Skin on Glass
Last edited by Withindale; 02/06/14 06:10 PM. Reason: PS
Ian Russell
Schiedmayer & Soehne, 1925 Model 14, 140cm
Ibach, 1905 F-IV, 235cm
|
|
|
|
|
Joined: May 2013
Posts: 1,131
1000 Post Club Member
|
|
1000 Post Club Member
Joined: May 2013
Posts: 1,131 |
In any case wouldn't it suggest there is friction to be dealt with?
PTG Associate
AIO Regular Member
ASCAP
Pipe Organ Builder
Chief Instrument Technician, Director, Chancel Arts
Church Music Professional
AA Music Arts 2001, BM Organ, Choral 2005
Baldwin F 1960 (146256)
Zuckermann Flemish Single
|
|
|
|
|
Joined: Dec 2012
Posts: 6,714
6000 Post Club Member
|
|
OP
6000 Post Club Member
Joined: Dec 2012
Posts: 6,714 |
I don't see how the jack would be capable of being driven at the range of frequencies and amplitudes that comprise the squeak.
In the case of waxing a car the cloth is the bow and the surface of the car is both the string and soundboard.
I wonder if the vibrating component is the sides of the rep lever where the jack window is.
In a seemingly infinite universe-infinite human creativity is-seemingly possible.
According to NASA, 93% of the earth like planets possible in the known universe have yet to be formed.
Contact: toneman1@me.com
|
|
|
|
|
Joined: Jun 2011
Posts: 824
500 Post Club Member
|
|
500 Post Club Member
Joined: Jun 2011
Posts: 824 |
I would consider the squeak to be a direct result of the frequency of the air being disturbed as both surfaces interact due to friction rather than either the leather or jack specifically.
|
|
|
|
|
Joined: Sep 2004
Posts: 2,685
2000 Post Club Member
|
|
2000 Post Club Member
Joined: Sep 2004
Posts: 2,685 |
The nap of the buckskin pointing away from jack escapement, favoring return may contribute??
x-rpt
retired ptg member
|
|
|
|
|
Joined: Feb 2011
Posts: 4,331
4000 Post Club Member
|
|
4000 Post Club Member
Joined: Feb 2011
Posts: 4,331 |
Fingers can squeak when rubbed against CD cases and through wet hair. Sounds like Johnkie and SM Haley are on the right track!
Ian Russell
Schiedmayer & Soehne, 1925 Model 14, 140cm
Ibach, 1905 F-IV, 235cm
|
|
|
|
|
Joined: Dec 2012
Posts: 6,714
6000 Post Club Member
|
|
OP
6000 Post Club Member
Joined: Dec 2012
Posts: 6,714 |
It seems like one, either the cloth or the wood surface, is the driver and the other is the soundboard. I suppose both could be vibrating but that would be most likely to produce two distinct ranges of pitch in the squeak.
Come to think of it the squeak often does have a lower "roarrrk" at the start of key motion and a continuous "screek" sound during key motion. But maybe I am hearing things.
In a seemingly infinite universe-infinite human creativity is-seemingly possible.
According to NASA, 93% of the earth like planets possible in the known universe have yet to be formed.
Contact: toneman1@me.com
|
|
|
|
|
Joined: Apr 2007
Posts: 3,332
3000 Post Club Member
|
|
3000 Post Club Member
Joined: Apr 2007
Posts: 3,332 |
It would be easy enough to adjust the jack high in the rep window so that the rep lever is not in contact with the knuckle through let-off. If the squeak persists it would prove that the rep lever is not responsible. You could also do the opposite by adjusting the rep lever much higher than the jack and see how the squeak is effected.
|
|
|
|
Forums43
Topics223,391
Posts3,349,282
Members111,634
| |
Most Online15,252
Mar 21st, 2010
|
|
|
|
|
|
|
