[CAUT] M&H "A" stability

[Don Mannino]

I'll put in a small addendum to John's message.  I agree with what he
said, but one must keep in mind other variables as well.  This also
depends on how springy the tuning pin is, for instance.

If you pull the string up to final pitch, with a high friction piano
that has high string coils and no plate bushings, the pin will spring
back some in the process of tuning up.  Then, on release of the pin, it
springs back and causes the string tension in the tuning pin segment to
go down again. Troublesome.

This would not be the case in a M&H, of course, but one does need to
experiment with some pianos.  If the pins are springy, then bouncing the
tuning down to pitch (without  turning the pin, just bouncing it a
little) for the last fine tuning can work well.  The spring in the pin
will re-tension the wire in the speaking length after you finish.   This
used to be my technique for those difficult Steinway uprights.

Some Kawai grands combine twisty pins (because of the very small pins)
and high string friction (partially caused by the intentionally soft
iron used in our plates) to lead to difficult stability in the capo
sections.  In these we find it's best to pre-load the pin by pulling
quite sharp, and settling it back down until the string is very slightly
flat.  Then the last fine tuning is done by springing the pin up to
pitch.  The pin will be slightly pre-loaded, wanting to untwist and move
sharp. Plus that last little bounce up for the fine unison tuning will
make sure the string tension is good.  It takes some thought and effort
to get used to, but once one gets the idea the process isn't bad.

Isn't piano tuning fun?

Don Mannino


-----Original Message-----
From: caut-bounces at ptg.org [mailto:caut-bounces at ptg.org] On Behalf Of
Jon Page
Sent: Wednesday, May 20, 2009 10:35 AM
To: caut at ptg.org
Subject: Re: [CAUT] M&H "A" stability

On any piano with high counter bearing (c/b) angles you can't finesse
the string/pin.

The high friction does not lend to fine adjustments. The best way to
tune these is to pull the string to pitch and leave it. This leaves the
tension between c/b and pin higher than the speaking length for a more
stable  tuning.

If you lower the tension, because of the friction involved, the pin to
c/b tension is extremely low and causes an unstable tuning.  On hard
blows the lower tension will creep through but a higher front tension
will hold the pitch on a hard blow.

There can be no pin setting style of the ever diminishing series of
raising and lowering tension to feel the torque in the pin and set the
string rendering with the final movement with a nudge up to maintain
higher tension between pin and c/b. Pull it up and move on.
Set it and Forget it, you're cooked.
-- 

Regards,

Jon Page