[pianotech] regulating S&S (ex-) reproducer actions

[pmc033 at earthlink.net]

Hi, David:
	I'm not a rebuilder, but I'll put in my $.02.  The difficulty with a
longer key lies in the geometry.  The hammers check because the arc of the
backcheck intersects the arc of the hammer tail.  The extra length of the
key makes the radius longer than a regular key, and so the arcs don't come
together until the key has moved a greater distance thru that arc.  Draw a
simple diagram with two different key lengths showing a side view and
you'll get it.  
	Also, beware the spring strength.  If you have a short blow distance, the
spring doesn't "wind up" as much, so it will take a greater tension to lift
the hammer.  
	FWIW.
	Paul McCloud
	San Diego

> [Original Message]
> From: David Nereson <da88ve at gmail.com>
> To: <pianotech at ptg.org>
> Date: 11/18/2009 11:04:59 PM
> Subject: [pianotech] regulating S&S (ex-) reproducer actions
>
>     I'm told by an esteemed rebuilder colleague that the 
> Steinway reproducer actions don't regulate quite the same as the 
> "regular" actions because the longer keys change the action 
> geometry.  He says he usually has to compromise something in the 
> regulation for better playability.
>     I regulated one (player system removed) after installing new 
> hammers & shanks and can't quite get rid of bobbling hammers. 
> Or, not so much bobbling as hammers not wanting to check on a 
> soft blow.
>     The key height is as high as it can be without interference 
> from the fallboard.  The blow is about as high as it can be (1 
> 5/8") -- any higher and the bass hammers won't fit under the 
> pinblock.  The dip was quite deep (almost 1/2") and I lessened 
> it to make it closer to 7/16".
>     The aftertouch is minimal.  It's there, but just barely.  I 
> know some say aftertouch should be 0.4 mm, which to my mind is 
> no aftertouch.
>     What prevents hammers from checking on a soft blow?  Seems 
> no matter how much I fool with backcheck angle and distance from 
> the tail, some of them just will not check.  No, I don't think 
> the rep springs are too strong.
>     Also the touch is too light -- about 45 grams DW.  Vertigris 
> infested the entire action, which was the main reason for 
> replacing shanks.  Customer's budget couldn't afford new wippens 
> or repinning all the rep levers, jacks, and wippen flanges, so I 
> "zapped" them all to free them up, tefloned the knuckles, 
> rebushed keys, & sprayed McLube on the keypins, since the action 
> was extremely sluggish before.  But maybe all that was too much. 
> I don't know how to make the touch heavier now except to repin 
> all the wippen parts or install new ones, or re-balance the keys 
> (move the key leads).
>     --David Nereson, RPT 
>