[pianotech] Backcheck height: how high is too high?

[Gene Nelson]

I installed a set on my piano using the kit and following their instructions 
to the letter.
After installation, checking was close to 1/8 inch. This close, the hammers 
go into check when playing piano or maybe slightly softer. The rep spring 
can be stronger and virtually no chance of double bounce with superior 
repetition.
Now I have them at 1/4" and will likely keep it there.
Seems to me that the surface area on the hammer tail that engages the back 
check is relatively small (about 3/8" by the hammer width - same with the 
back check surface area that catches the hammer tail -  if checking is 
initially at 1/8" before any adjustment is made and the hammer tail surface 
is relatively centered on the back check - checking efficiency will be 
reduced if you set checking height lower than 1/2" - so I never did try 
5/8".
As checking at 1/8" is not possible (in my experience) with the traditional 
back checks and arcing of the tails, who is to say what is ideal? This is 
something new.
Gene
----- Original Message ----- 
From: "Kurt Baxter" <fortefile at gmail.com>
To: "Pianotech List" <pianotech at ptg.org>
Sent: Saturday, February 05, 2011 4:50 PM
Subject: [pianotech] Backcheck height: how high is too high?


> So if anyone has installed a set of WNG backchecks (when using their
> jig system at least), you know how easy it is to get the hammers to
> check literally as high as you want.
>
> This raises the question: what *is* the ideal checking height? What
> happens when it get too high, and how high is that?
>
> I have heard "as high as possible without binding" as often as I have
> heard 5/8", so that make me wonder if 5/8" is actually ideal, or
> somewhat arbitrary.
>
>
>
> -kurt