Grand regulation...

[Avery Todd]

Michael,

First, two questions.

1. Is the piano in a home or a dealership? In other words,
    who's going to pay for the work? Warranty?

2. Is the customer complaining about how it feels/responds?
    Just curious.

OK, terminology differences aside, I'll attempt a few comments. :-)
I'm probably going to tell you things you already know but since
I "don't" know........

First, make sure both of your jack positions are correct in relation
to the knuckle (roller) and that you have at least "some" repetition
(rise). You can do final adjustments on this later but you need "some"
rise to be able to set a stable hammer line.

At 09:20 PM 10/08/03 +0100, you wrote:
>Hello all. This is an attempt to get some input from those who (that means 
>all of you I guess) frequently regulate grand actions. From the start we 
>have a few hurdles to get over and of these the principal one is that of 
>terminology. In regulation you get a) the parts which are being regulated 
>and b) the name given to that part of the regulation process. Are we at 
>one with the name "striking distance"? which should be about 1 7/8"

We usually call this blow distance and can be somewhat
variable depending on the key dip (depth) you need to have
the aftertouch you want. I personally prefer, in most cases,
for the dip to be in the 9.5 mm to 10.0 mm range.

>Then we have "Set-off" In this part we adjust the "Set-off Button" until 
>it touches the toe of the "Jack" and causes the hammer to stop rising and 
>go into the "escapement" mode.This Set-off happens about 1/16" below the 
>string.

This setting is usually acceptable in most cases, except with it
being perhaps a little closer in the high treble and a little
wider in the lower bass.

>Next we have the "Let-off" (I think that's sometime called "Drop") when 
>the hammer after hitting the string is allowed to subside another 1/16".

Also generally acceptable.

>Not to be confused with "Check" when the hammer after hitting the string 
>more forcibly rebounds into the loving grasp of its check-block.

I like to have the hammers check a little higher than the 5/8"
usually mentioned, without having the hammer tails rub on the
backcheck. A lot of techs set them as high as possible to help
enable faster repetition.

>If then, whilst the hammer is captivated in check you gradually release 
>the key the hammer should float upwards - not too fast. This we call 
>"Hammer rise".. OK?

I like to set this for them to rise as quickly as possible
without feeling a "jerk" in the key when it comes off the
backcheck.

>The point of all this is I went to tune a new Petrof grand the other day 
>and was amazed by how much this Czechoslovakian manufacturer had deviated 
>from what I considered the "norm". The results were as follows:
>Striking height 1 7/8" (OK)
>Check 13/16" ?
>Set-off 1/8"!!!
>Let-off 3/8"!!!!
>And the hammer-rise test showed that all the hammers came up faster than 
>you can say knife!

Just because that's the way it is, doesn't necessarily mean
that's the way it should be, or even the way the factory
intended it to be. :-) I service a few Petrofs here in Houston,
and I've never run across that much of a deviation before.

>Here's the question therefore -
>What are the correct settings?

My personal philosophy is that regulation specs are usually
good guidelines but not "set in stone", so to speak. There
can be all kinds of reasons why one might need to deviate
from them to get the best possible regulation. For instance,
I've run across some instruments where the hammers had
been bored incorrectly and to make the action work
acceptably, I had to compromise with the key dip and
blow distance.

IMO, the first thing you should do is set a few guides
in the piano and see if everything will work correctly.
Raise the letoff to 1/16" on a few sample notes and see
if you still have enough aftertouch. With that much letoff,
maybe the dip is too shallow and rather than correct that,
someone just increased the letoff in order to get the needed
aftertouch.

Since you didn't mention that term in your post, to be sure
you understand what I'm saying, aftertouch is the distance
the key moves AFTER letoff (set-off). You need to have enough
so that the jack will clear the knuckle but not TOO much or
the jack could "jam" into the cushion felt in the wippen.

If the letoff change tells you that the key dip is OK, then
go for it on the entire piano and make the other adjustments
as needed.


>My Steinway service manual adheres pretty firmly to my first list of 
>requirements except that the "Let-off" is considered with relationship to 
>the diameter of the string affected.
>Oh yes - there's another aspect of regulation. It's vital that the "Key 
>depth" be correct. Steinway recommend 9.75 on models S - B and 9.75mm on C & D.

I don't have my manual here at home to check but these are
the same measurements!?

>At the end of the day does the piano react as a concert pianist would expect?

Hopefully. :-)

>Over to you.
>Michael G (UK)

Sorry about the length of this but with grand regulation, so many
things are affected by other things, that it's just hard to put all
the possibilities into words but I hope this helps a little.

Avery