[CAUT] Key bottoms

[Mark Cramer]

Hi Barbara,

we had an older Yamaha G-2 with balance-holes ovaled fore & aft to nearly
twice the size of the rail pin. (!?)

Some keys literally had an 1/8th inch of pulley, making it difficult in some
cases to determine where the original hole-center was.

Obviously this isn't normal wear and tear. ( I'm guessing someone forgot to
read the fine print on their new easing tool)

Nonetheless, we used Bill's method (PT Journal; May 1990) during the course
of rebuilding the action; fall of 2005,  and the keys continue to fit and
work beautifully.

There was a fair amount of alignment needed with the initial fitting, but
I'm guessing this was more my inexperience than the method itself.

best regards,
Mark Cramer,
Brandon University

PS Floyd is back here in Manitoba, Barbara. He's just applied for membership
to the MB Chapter, and is helping access/repair vertical practice pianos.
He's intent on completing the exam series, and I'm glad to have his help in
the shop.






  I can see that this method would be better and more stable than squishing
wood.  Is there anyone with experience with it from the Far North, Midwest
or Northeast where we go through <huge> seasonal swings in humidity levels?

  Thanks.

  Barbara Richmond
  on the way out the door to pick up a S&S B action w/key bottom trouble


    ----- Original Message -----
    From: Keith Roberts
    To: College and University Technicians
    Sent: Thursday, July 26, 2007 10:14 PM
    Subject: Re: [CAUT] Key bottoms (was Re: key-easing pliers?)


    When I replaced the balance rail holes ala Spurlock, I drilled them
slightly smaller the first pass and they were tight, really close. I took a
1/8" chainsaw file that mics at .130 to .135 on the cutting surface and it
was tight so I inserted the file in the hole and rotated 1 turn
counterclockwise and removed. (I had to make a handle). They were perfect on
the new pins.
    Lucky me.
    So I ground off the back and sides of one of those files till I could
taper the hole until the key rocked nicely and leave the bottom untouched.

    And when I checked them 2 years later they are still perfect.

    Keith Roberts


    On 7/26/07, Fred Sturm <fssturm at unm.edu> wrote:
      On Jul 26, 2007, at 11:46 AM, Jim Busby wrote:
        Fred,

        One difference/question I have is - isn't it easier to insert the
proper sizing cauls, then turn the set upside down and insert the BR pins
(the cauls won't let the pins fall through), then add sizing fluid? After
they dry, ream the mortise so the "foot" of the hole is the exact thickness.


      Takes a long time to insert those balance pins in each hole, and then
pull them out later (I don't have a bunch of student helpers, so a few
seconds here and there on each little procedure add up). I'm "reaming" with
a drill bit, which doesn't remove as much wood as a real reamer, and maybe
leaves a bit of "uncut splinters" (we're talking fairly microscopic) to hold
glue if I need to size later. That's my reasoning, anyway. And I think it
leaves a more stable condition than just putting in BR pins and letting the
wood conform to them, if your holes are too small to begin with. I'm closer
to having the right amount of wood (in this dimension, not to be confused
with the reaming you are talking about above). Making the hole exactly the
size of the pin will require a bit of easing. So I use one sizing caul,
which is heated. The heat increases the size of the balance pin in the caul
from .146" to .147", and the heat helps size the wood - make the size
relatively permanent. It puts the hole .001" larger than the pin, very
nicely and consistently. (Glue-sizing to make the hole smaller where needed
is a separate part of the procedure, done only to holes that are too large).

        Replace them on the Keyframe to check BR fit and fix pulley keys.


      That's a lot of time and work. I like to leave the keys in the clamp,
and bring the balance pin to the key. I can feel that pin going into the
hole very precisely, and also feel if there is any play in any direction..

        Many times pulley keys are no longer an issue with the glue sizing
formula. BTW I use a much diluted (12/1 or so) Elmer's glue for sizing. Ron
N. tells me that this is the only place on a piano where he uses that glue.
(Thanks Ron) There is no sound, click, etc. with Elmer's glue as there is
with PVCE, Hot Hide, and or other glues.



        Baldassin taught me to add this extra step (it really doesn't take
long) of placing the keys back on the frame BEFORE the bushings are in so
that you can work the BR holes w/o "false readings" from overly tight new
bushings. It takes about 10 – 15 minutes longer but the total focus on the
BR hole pays big dividends, IMO. Here is when I deal with the pulley keys
because now you're sure of which ones weren't fixed by the glue sizing.

      Rick B is certainly correct in wanting to separate bottom hole from
bushings, so one doesn't mask the other. I think I do it with a lot less
time and effort. Putting a loose pin into the hole removes the factor of the
weight of the key. All that lead can mask a lot of problems.
        Anyway, just a bit more to consider for your book... Who knows?
Marriott's success, he said, was to "write out every tiny process and revise
it in writing until nothing more could be perfected, then get all your
employees to do it THAT way."

      I don't like having employees other than myself. That's one reason I
am in this business <G>.
        (I vote for you to write that book, sometime before your beard is
entirely gray?? You and Ron. Oh well, Ron…))

      I don't think there's much chance of me compiling and writing in book
form. But if anyone else wants to do that, and make use of what I have
posted from time to time, that would be fine with me. Have at it with my
compliments.
        High regards,

        Jim

      Regards,

      Fred

-------------- next part --------------
An HTML attachment was scrubbed...
URL: https://www.moypiano.com/ptg/caut.php/attachments/20070727/881b03c1/attachment.html