[pianotech] regulation "sweet" spot

[Fenton Murray]

I'm just picking up this thread and would like to add a method for setting 
drop.

With let off set and drop too low and the action on the bench.
Place weights on the key amounting to 5 grams or so over the down weight.
Let say down weight is about 52, try 56 or 57 grams.
The key will drop until the drop screw contacts the leather.
Now, raise the drop and watch the hammer rise, when it stops rising the jack 
heal has made contact with it's button.
You now have simultaneous contact between drop and let off.
Fenton
----- Original Message ----- 
From: "John Delacour" <JD at Pianomaker.co.uk>
To: <pianotech at ptg.org>
Sent: Tuesday, January 20, 2009 2:23 PM
Subject: Re: [pianotech] regulation "sweet" spot


> At 14:12 +0000 20/1/09, Steven Hopp wrote:
>
>>...(This is my first full grand regulation).
>
> Don't beat yourself up, then, if it's not as full as it should be.
>
>>I am having some trouble on a few notes not finding that "sweet" spot of 
>>let-off to drop ratio or point.  I am using a let-off rack set to baldwin 
>>spec of 1" 7/8" and have levelled the hammers for a proper blow distance.
>
> As others have suggested, hammers should be bored to suit the individual 
> piano; otherwise the result will never be ideal.  The factory bore is 
> often wrong and it is almost always possible to get the piano sounding 
> better than it ever did, especially in the high treble, by boring the 
> hammers exactly -- but it's too late for that now and it's a long subject.
>
>>   The majority of the notes are good and behave as expected. i.e. a slow 
>> rise of hammer to a 1/16" below string strike with a 1/8" drop with that 
>> little bump (what I call the sweet spot) in the feel of the key as you 
>> play.  Granted on the good ones some of the "bumps" are stronger than 
>> others but on some it is very weak or on the bad notes it is not present 
>> at all.
>>
>>The questions I have are:
>>
>>1.  What should I do when I can not get the two Let off and drop to 
>>reconcile?  (good rise vs. too much drop or poor rise with that magic bump 
>>in the feel)
>>
>>2.  If I get the regulation button turned so low that there is no more 
>>turn left and I am not getting good results what should I do after 
>>starting back at beginning of that notes regulation?
>
> The chances are, as has also been suggested, that either you have the drop 
> screws too high or you have insufficient touch depth.  The set-off 
> (letoff) is always adjusted before the drop, but you can't do the set-off 
> unless you have previously screwed down the drop screws, which, in the 
> case of a piano that has worn and been regulated, will always be too high. 
> So, roughly lower the drop screws so that you can regulate the set-off.
>
> Contrary to someone else's advice, I always leave touch depth till last 
> before finally regulating the drop, and I have good reasons for this.  If 
> your blow is exact and your set-off good, then the desired touch depth 
> will be that which brings the jack just clear of the roller (knuckle). 
> With the drop regulated fairly accurately you can regulate the touch depth 
> until you get just the right kick, and this is best done by feel with the 
> action in the piano.  When this is done, finally regulate the drop, and 
> then recheck the kick (or aftertouch).  If the aftertouch is excessive --  
> the jack is pushed against the slap cushion and there is a marked kick --  
> then the regulation is inefficient, the touch is too deep.  Once the 
> hammer has dropped onto the cradle the key should be bottomed so that the 
> hammer can only be made to rise by pushing the key hard into the keybed. 
> Some actions will exhibit no rise of the hammer after drop, but with most 
> standard Erard-Herz actions the hammer will rise very slightly during the 
> aftertouch.  But the less aftertouch you have, consistent with clearance 
> of the jack from the roller, the better it is.  There is absolutely no 
> virtue in kick for kick's sake.
>
> These operations all come very near the end of the process of "grand 
> finishing".  Regulation begins with a whole series of far more basic 
> measurements and alignments, as we all gradually learn!
>
> JD
>
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