wasted CA on grand pinblock

[David Nereson]

  -----Original Message-----
  From: William R. Monroe [mailto:pianotech at a440piano.net]
  Sent: Wednesday, November 08, 2006 5:59 AM
  To: dnereson at 4dv.net; Pianotech List
  Subject: Re: wasted CA on grand pinblock


  Dave,

  How much CA did you use?  It's about $10 for 2 oz., (and as I
wrote earlier, I'd rarely use that much for an entire block) not
real expensive in my book, if it can keep an instrument tunable
till a rebuild is possible (or the piano is junked for other
reasons).

         Yes, I did use almost an entire 2 oz. bottle.  I'm just
frustrated with buying CA glue and having it set-up solid in the
bottle before you even get to use it all, and it's considerably
more costly than other glues.
      Anyhow, yes, I probably used too much and that's why it
leaked out and dripped down the flange.  I did use a hypo oiler,
but you can't really tell how much is going in there.  The pins
had all been driven in already, so the coils were quite close to
the plate.  I didn't want to glue the coils to the tuning pins
or the strings to the plate, so I held the tip of the oiler
right down in the hole.  Aside from how fast the bottle is
emptying, you can't really tell how many drops per pin are
flowing out.

  -----Original Message-----
  From: pianotech-bounces at ptg.org
[mailto:pianotech-bounces at ptg.org]On Behalf Of Frank Emerson
  Sent: Wednesday, November 08, 2006 8:49 PM
  To: Pianotech List
  Subject: Re: wasted CA on grand pinblock


  How do you know if there is a gap between the pinblock and the
plate?

  I had a bright light, and with no tuning pin bushings, I could
almost see the gap, at least in the few tuning pin holes where
the pins hadn't been driven in.

   Tighten the pinblock screws.  If you find that they can be
tightened even a little, the gap described in the original post
probably did exist, before tightening the screws.  With about 20
tons of combined string tension pulling on the pins
significantly above the top surface of the pinblock, the tension
will pull the pinblock up to the plate at the stretch side of
the block, and down, away from the plate at the plate flange
side.  This is encouraged by the draft angle of the plate flange
(about 7 degrees), matched by the angle of a well-fitted
pinblock.  Even this slight angle of incline constitutes a ramp
to further encourage movement in this direction.


  So you're saying the pull tends to create a gap between plate
and block towards the flange side of the pinblock?

  I have no experience with CA treatment of pinblocks, but in
light of the problem presented in the original post, I would
suggest tightening and retightening all plate screws before CA
treatment.
  . . . . .

  Frank Emerson
  pianoguru at earthlink.net



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