Qwestion about lost motion tests

[Alan Barnard]

Just a small nit to pick. You described a "smooth topped plastic jack (such as Kawai or Yamaha)", but at least in the Kawai, it is NOT smooth. They found that a little bumpiness on top makes the jack work better. Don Mannino can explain better than I. 

Another HUGE factor, especially in older pianos, is sluggish return of jacks or hammer butts, i.e. pinning problems, dirt, worn bushings, springs broken or weak or out-of-place, etc.

Yet another, potentially huge factor is aftertouch. I've seen older pianos with so much dirt, slut's wool, mouse nesting and other crud under the keys that they just won't allow the action to fully cycle. In fact, in a really out of reg old beater, when all else fails and you are going nuts trying to get a jack to reset without have a quarter-inch of lost motion, try removing a front rail punching or two and watch the magic (sometimes). Please do not do this on a Steinway D just before the concert: but on Granny's old Cable upright, have at it. 

Alan Barnard
Salem, Missouri


----- Original Message ----- 
From: 
To: Pianotech List
Sent: 05/04/2006 6:55:21 PM 
Subject: Re: Qwestion about lost motion tests


Julia-

The purpose of the lost motion is to allow the jack to reset under the hammer butt on a very slow release of the key.  What you need for this will vary considerably from piano to piano.  

For example, on a good quality new piano with a smooth topped plastic jack (such as Kawai or Yamaha) there may be no perceptible lost motion, but the jack will still reset.

Another piano may need the tiniest perceptible lost motion made as even as possible. You might tug on the hammer rest rail to see if all the hammers move back the same tiny amount.

On a console with worn key bushings, twisted keys, irregular level and dip....do what you can to make it better and move on.  Sometimes perceptible improvement is the best you can offer.

Ed Sutton


-----Original Message----- 
From: KeyKat88 at aol.com 
Sent: May 4, 2006 5:17 PM 
To: pianotech at ptg.org 
Subject: Qwestion about lost motion tests 


Greetings,

         There seems to be a gray area about lost motion for me. In an upright or console, when all the keys are resting or balanced on their own weight, and if I push alittle on the top of the key to test lost motion amount, the check and hammer simultaneously move by my doing this. It is indicative of NO lost motion. Right?  However, if I grab the key between my fore finger and thumb and move the key up and down then I see a sustantial amout (1/32" to 3/64") of motion. Then what?

        Which test is the truer test? In school, they taught us to just lightly tap on the top of the key and if the check winks slightly without winking the hammer then that is the lost motion. However, working with used pianos, I have discovered that if I secure the key between my fingers and move it up and down this will show me lost motion, even though the 'top of the key tap' test shows me there is none. 

     It seems there is a conflict, and geeeesh(!) there can be differences in the amout when two (let's say, for the sake of making my point obvious) two white keys side by side are set the same for the 'top of the key tap' test and when I use the 'up and down' test they can really different amounts from one another. What gives?

      
Thanks in advance
Julix Gottshall
Reading, PA 
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