[pianotech] Best way to change touch on Yamaha Grand

[William Truitt]

Thanks Vladan, your explaination is clear now.

Will

-----Original Message-----
From: pianotech-bounces at ptg.org [mailto:pianotech-bounces at ptg.org] On Behalf
Of V T
Sent: Wednesday, January 06, 2010 7:11 PM
To: pianotech at ptg.org
Subject: [pianotech] Best way to change touch on Yamaha Grand

Hi Will,

I think, the original idea was to put a punching down (around the pin) and
spot glue one half of it to the balance rail. Then, you cut some of the
unglued end off. For example, if you are trying to reduce the ratio, you
would, put a spot of glue on the side of the balance rail that is facing
towards the hammers. When the glue dries, you cut some portion of the
unglued side of the punching off. This makes the key pivot on the edge where
you cut. It's a little more complicated than that, because the pivot point
is constantly shifting, but in essence, you are removing any possibility for
the key to pivot on the edge that you just removed. I hope I explained this
well.

Nowadays, I think most people will glue a thin strip of wood along the
entire row of pins. The distance between the edge of this strip and the
balance rail pin determines how much you end up changing the ratio. It only
takes a little to get a noticeable change. Then, you put your normal
punchings over that. I don't have a photo handy, otherwise I would post it.

Vladan

============
"Vladen, could you explain a bit more completely
how you go about doing this?  I am having trouble visualizing your shim -
fulcrum in terms of material used and its co-existence with balance rail
punching and felts.  Thanks.

Will Truitt"