[pianotech] WNG jack don't come back no more, no more, no more.....

[Encore Pianos]

Ok, Dean:

 

Combine the too heavy gauge of wire for the hammers with rep springs where
the coil flops around on a too small barrel (.050 difference) along with a
jack top that is visibly smaller in width and length than other comparable
grand jacks (the WNG jack is, and that means that the top of the jack is
carrying a much higher load than a comparable jack, and would therefore have
more difficulty getting back under the knuckle).   When I strike the key and
the hammer goes up and trips through let off and then settles in to the
backcheck - if I slowly release the key and watch the jack moving to go back
under the knuckle as it rolls, about 2/3 of the way through the stroke, I
see the jack hang just a tad for a brief moment before it continues until
the button contacts the jack rest felt.  It will also mean that sometimes
following a soft blow, the jack will go back under  the knuckle most of the
way but not all the way, and you will get these drive you crazy intermittent
cheaters.  Finessing the fore and aft position of the jack  seems to have
little effect on this.  Ask me how I know all this.  Add stripped jack
adjustment screw holes where they just spin but do not really move to
further confuse me.  Add to this the jack stop felt in the window being too
thick so that you cannot adjust the jacks back far enough, also my
experience.    

 

Add jack resistance measures of 7 or 8 grams instead of 1 or 2.   If you
release the jack slowly to see it try to go back under the knuckle it will
still hitch at a certain point, no matter how strong the rep spring is.  I
suspect the rep lever profile in the area of the knuckle may be
contributory, but that is above my pay grade in terms of action geometry.
If the hammers are heavy, this will further  exacerbate the situation.  

 

My solution to these too heavy guage rep springs was to repin the rep lever
posts at about 10 grams to slow the karate chop kicks of the hammer from the
springs so that you would get a much slower and controlled rise.  The too
heavy springs make the adjustments hypersensitive and a giant pain in the
ass to regulate.  Also, I pushed out the too small barrels, reamed the hole
in the post to a larger size, and threaded action cloth through the coil
along with a center pin to stiffen it.  The rep spring  coil had no play at
this point, and rep spring adjustment was far more consistent and the action
felt more controlled and positive.

 

By the way, all this was on an early set of cloth bushed WNG parts made 2
years or more ago.  I suspect that in Ed Foote's case, some of these issues
may remain while others may have been addressed, as I had long conversations
with Bruce Clark about these issues some time ago.  

 

Will Truitt  

 

 

 

-----Original Message-----
From: pianotech-bounces at ptg.org [mailto:pianotech-bounces at ptg.org] On Behalf
Of Dean May
Sent: Thursday, January 19, 2012 9:04 AM
To: pianotech at ptg.org
Subject: Re: [pianotech] WNG jack don't come back no more, no more, no
more.....

 

I'm having trouble understanding so I'm going to risk asking a stupid
question. Could you or someone explain why the too heavy spring could be the
problem? I understood the complaint to be the jack would not slip under the
knuckle. Seems like too much rep spring tension would assist in holding the
rep lever high to make it easier for jack to return, not more difficult. 

 

Thanks in advance.

 

Dean

 

Dean W May (812) 235-5272 voice and text

 

PianoRebuilders.com (888) DEAN-MAY

 

Terre Haute IN 47802

 

 

-----Original Message-----

From:  <mailto:pianotech-bounces at ptg.org> pianotech-bounces at ptg.org
<mailto:[mailto:pianotech-bounces at ptg.org]>
[mailto:pianotech-bounces at ptg.org] On Behalf Of Ron Nossaman

Sent: Thursday, January 19, 2012 8:56 AM

To:  <mailto:pianotech at ptg.org> pianotech at ptg.org

Subject: Re: [pianotech] WNG jack don't come back no more, no more,no
more.....

 

On 1/19/2012 7:22 AM, David Stanwood wrote:

> Hi Ed,

> 

> I've seen this problem w/WNG and attributed it to a rep spring that is 

> too heavy a gauge for the hammer weight.

 

This makes a whole lot of sense. I've seen this situation in mechanisms
other than piano repetitions, where the spring rate is too high and the
adjustment is finessed at the limit of travel to try to make the thing

(almost) work. When a very small adjustment in the spring makes a much
bigger than it should difference in the reaction, this is a good indication.

 

Ron N

 

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