YC Strike Weights etc

[David Love]

----- Original Message -----
From: "Richard Brekne" <Richard.Brekne@grieg.uib.no>
To: <pianotech@ptg.org>
Sent: November 02, 2001 2:13 PM
Subject: Re: YC Strike Weights etc


> What do you mean by "convergence line" ?

The magic line between the bottom of the balance rail hole in the key and
the wippen center pin.  If the top of the capstan rests on this line at half
blow there's not much point in thinking about moving it unless you have a
problem that you can't solve otherwise.

The reason I think that it's important to know the BW is that you don't know
where your FW's should be if you have no point of reference.  I think it's a
mistake to rely to heavily on the assist spring.  Nine or ten grams is
plenty (though I think you can go to 15 with problems of bouncy keys).  By
comparing the BW with the FW's (with assist springs detached) you can tell
how much you will have to rely on the assist spring with the FW's at or
comfortably under maximums (I prefer to set them at 10-15% below maximum).

> But if I had gotten enough pay on this.. you would suggest resetting the
> black balance rail pin positions ?

You would have to remake the black keys, or at least figure out a way to
plug the current holes, remortise, redrill and reconfigure the balance rail
itself to accomodate the new pin position.  I've never done it so I don't
really know.  Since the sharps are weird anyway with the magic line not
passing through the capstan the same as the naturals plus relatively short
length, I probably wouldn't worry about it.  They have a bit of a different
feel anyway.  Might be a reason to keep the FW's a little lower on the
naturals though.  With the higher KR on the sharps you will have
corresponding higher FW's to accomodate weaker force leverage.  So you might
consider keeping the sharps at FW maximum and allowing the naturals to come
in a bit lower.

David Love