Pleyel Grand Regulation Questions

[Stéphane Collin]

Hi Will.

 

I found several conflicting sources about the specifications for that Pleyel
action.  I myself do think that the action you are describing should
regulate about the same way another would.

Apart from the key height that is more like 53 mm, I start with the usual
figures, see what happens.  The 10 mm key dip works well (while you will
hear people say they used 9 mm ; I myself think that the 9 mm dip is valid
for the Pleyel pianos from before 1860 or so, with the English action).  The
blow distance should be maximal, as long as you leave a gap between the
shank at rest position and the rest rail.  If you can’t achieve a complete
escapement cycle with some aftertouch, simply raise the hammer rest
position.  Let off and drop work the same way as in the Erard-Hertz action;
Those ennoying T shaped drop screws regulate only by half turns, which
proves often not to be precise enough to get nice results.  What I do then,
at the cost of premature wearing of the leather concerned, I fine regulate
those by giving a minute portion of a turn more, so only one side of the T
shape hits the leather, but with its angle, you can achieve better drop
precision.  You’d better make a dedicated tool in wood to avoid scratching
those T shapes.  Did I understand that the jacks rest position is determined
by a piece of fluffy felt, and no screw to fine regulate it ?  Yet the jack
position against the “nose” of the shank is crucial : if everything seems
right with the action spread, and the jack rests in the whippen window at
the place that is probably marked one or another way (sometimes with a
pencil mark, only at the extreme whippens of a section), it should be good.
To fine regulate the jacks alignment, you can “voice” the piece of felt on
which they rest : take a needle and needle that felt so it expands a little
bit, and the jack will rest a little closer to the hammer rail.  Opposite,
press the jack hard on that felt in order to have it rest farther away from
the rail.  Beware, there is very little room to allow for jack traveling in
the window, so anything away from the correct position will cause the jack
to hit prematurely the second piece of felt intended as a bumper at the
other side of the window opening.

I regulate the let off as close to the strings as possible, that is when a
very soft blow with dampers lifted doesn’t cause any wobbling of the hammer
against the string.  You can get a clear perception of an ideal blow feeling
where there is absolutely no, even minute, blocking of the hammer against
the string.  Depending on the period of year you are regulating, you may
want to add to this ideal minimum distance whatever you feel is necessary to
compensate for hygrometric changes in the other period of the year.  Indeed,
minimal drop works well.  But you will need dedicated tools to avoid ruining
the very fragile regulating screws.

The backchecks should be as high as possible, making sure they don’t
interfere with the hammer raising to the string, even when their inertia is
taken into account, which is validly simulated by travelling them up while
one hand presses downwards on them.  Sometimes, as their hammers are far
from any standard hammer, the use was to refelt them, and more than often,
the guy who refelted them put too much felt on the shoulders, causing the
hammer to hit the backcheck at rest (I’ve seen that many times).  You should
then severely reshape the shoulders, or consider refelting, but when
refelting don’t forget to mention the target total hammer length (and/or
bore distance) that will give you the desired hammer position against the
strings at impact time (and/or shank position).

To align hammers under the strings, first check that the action frame is
well positioned on its bed (replace the side felt accordingly if not).
Then, the only way to go is by warming the shanks with a flame and bending
them in the direction they should go, sideways and rotation ways.  Beware
not to stress the center bushings, or you ruin the friction consistency.  By
the way, if you rebush the centers on the shank, the only way to go, as
there is only one pin for 13 shanks, is to properly ream the bushings and
try the swings tests on the long “pin” rod that you will use.

I found those actions to be relying on a good regulation : anything away
from simply right will not function well.  But well regulated, they do
perform well.

 

I hope this helps, and that other techs used to Pleyel actions will comment.

 

From: pianotech-bounces at ptg.org [mailto:pianotech-bounces at ptg.org] On Behalf
Of Will Truitt
Sent: dimanche 29 juin 2008 2:34
To: 'Pianotech List'
Subject: Pleyel Grand Regulation Questions

 

To the List (particularly readers on the other side of the pond)

 

I’m regulating a 6’ 6” Pleyel grand (serial no. 72F691).  I’m guessing it’s
90 to 100 years old.  I haven’t seen that many Pleyels, and this is the
first one I have regulated.  And there are some differences from standard
fare, at least on this one.  I don’t have a digital camera, so you’ll have
to bear with my descriptions.  

 

It is a double escapement action, but having both let off and hammer drop
adjustments. (the drop screw mechanism is in the shape of a T, and is
adjusted from the underside of the shank rather than above.   There are let
off dowels, but they are adjusted through round holes through the top of the
hammer rail.  Of course, this means you cannot adjust let off in the piano
but rather must be done on the bench.  (the pinblock is in the way!)  There
are no separate hammer flanges, but rather a brass rail for each section,
with a single center pin running through all the shank action centers.
Rather than a rounded knuckle as we normally see in modern grands, the
“knuckle” profile resembles an upright butt, with a rest felt beneath a
somewhat rounded off leather profile from which the jack escapes.  A rounded
upright shank exits this butt and the hammer is glued to it.  

 

The whippens look different too.  The whippen flanges screw to the whippen
rail from below.  This rail is quite thick and is covered with felt on top,
and doubles as the hammer rest rail.  The jack looks fairly conventional,
except there is no fore – aft adjusting button but there is the adjustment
for the height of the jack in the rep top lever window.  That window is what
I would call a half window, in that there is no back side to it, with the
butt leather resting on the front portion.  The repetition spring is a
tapered coil that goes into a round slot on the back side of the jack, and
is adjusted from above with a regulating screw.  

 

The question I would be asking of those of you who may have some experience
with these actions would be what kind of idiosyncracies should I be looking
for in adjusting this action?  I don’t have any specs to work from.  What
kind of blow distance would be suggested?  Same for hammer drop, as well as
other regulation points.  

 

I do have some concerns about repetition.  I leveled the keys today and set
the let off.  I did test regulate a few notes and I did notice that I was
having some problems with cheating jacks upon a slow release of the key.
When the jack escapes, it rises rather steeply away from the butt leather.
Unless I make the rep spring very strong, the jack will hang up and not
return under the profile.  The height of the jack in the window did not seem
to affect this much.  I am guessing that this would be an action where a
shallower aftertouch would be desirable.  (Although that will have to be
moderated by the fact that it’s summer and the lake is 20 feet away.  If I
set too shallow an aftertouch now, by January it won’t cycle through let
off, I can guarantee you that).    

 

What kinds of regulating values are going to allow this style of action to
perform optimally?

 

For those of you who reply, thank you in advance.  

 

Will Truitt

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