Mason & Hamlin upright

[Isaac OLEG]

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Re: Mason & Hamlin uprightI guess I'll again will give the impression of a
very frustrated guy, but :

a : these spring add a springy feel at the end of the stroke, so the pianist
tend to play a tad stronger to override that sensation, then he produce less
dynamic range.
b : they eventually are getting you in trouble against checking and hammer
coming back at rest
c : then its easy, you regulate the rail so the springs don't act anymore
but then :
d : the added mass they provide on the jack is slowing the jack - for the
kind , U shaped I refer to.
d : the only remaining solution is to get them out.

I am unsure as I did not seem much of them recently on Seiler, Saunter,
Pleyel, but a locas piano shop in Paris is providing them and have a patent
on a U shaped spring they install as an option with a dab of glue on the
vertical part of the jacks, and this model I see regularly and find it is
useless anyway.

I am unsure that I have seen others that where installed on a rail and
pushing on a felt located on the jack, but, even if the sensation look
pleasing at first, after farther analysis one realize that there are too
many drawbacks to the slight faster jacks return they provide - mostly the
touch change the dynamic properties of the instrument too much.

Well another take by

Isaac OLEG (TM)


-----Message d'origine-----
De : pianotech-bounces@ptg.org [mailto:pianotech-bounces@ptg.org]De la part
de Keith Roberts
Envoyé : dimanche 7 mars 2004 19:37
À : Pianotech
Objet : Re: Mason & Hamlin upright


I'll be working on it again towards the end of the week. I can take pictures
and will see if I can't get them posted soon thereafter.
Basically it looks like a miniature of the flat steel spring used on the
pedal trapwork. An eyeglass size screw and pin fastens it to about the
middle of the jack. There is a 1/4 inch thick piece of felt glued on the
back of the catcher covering the hole the bridle strap comes through. As the
jack trips out at let off, the spring pushes against that felt on the
catcher and forces the hammer back towards the strings. There is a slight
backwards wink of the hammer before the hammer goes forward. It is my
feeling that the amount of wink should be the same and it should be
sufficient enough to achieve a proper checking distance. In this case I
think the checking distance should be 1/2 inch because the spring adds to
the acceleration on repetitive blows but any less distance weakens the force
of the blow too much.
As I write this I'm getting the feeling I want to mess with the thickness of
the felt instead of the spring or I'll end up with one of those actions with
all those pieces removed. (broken). Is it worth it? When this action is
working at it's optimum, it probably performs quite well. If I am not going
to bring it back to spec I can see a possibility that hammers could block as
regulation goes out.
Does anybody know any different from what I'm assuming here? Checking
distance, etc.
Keith Roberts
  ----- Original Message -----
  From: Keith McGavern
  To: Pianotech
  Sent: Sunday, March 07, 2004 7:58 AM
  Subject: Re: Mason & Hamlin upright


  At 11:08 PM -0800 3/6/04, Keith Roberts wrote:
    I'm working on one of those  M&H uprights with those flat brass springs
between the jack and the hammer butt catcher. Is there an adjustment for
those? ...


  Keith,


  Any chance you could get a pic of that device? I don't recall ever seeing
that arrangement.


  Keith
--
Keith McGavern                                    Texas State Association
  Registered Piano Technician                 SOONER SPRING SEMINAR
  Oklahoma Chapter 731                            March 11-14, 2004
  Piano Technicians Guild                        http://www.ptg.org/tsa/
  USA


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