Pinblock separation

[Michael Magness]

On Fri, Feb 29, 2008 at 12:04 AM, Fenton Murray <fmurray at cruzio.com> wrote:

>  Paul,
> You say your tuning in the treble and those notes went flat but not the
> bass, yet the crack is in the bass. Whatever, if the crack is clean and
> white like it looks it might of just happened, in anycase, that crack spells
> 'this piano can't be tuned' in my book. You can probably fix it by lowering
> the tension, closing the crack up as much as possible with clamps and
> replacing screws with through bolts and adding bolts as necessary. When
> you've got it where you want it, let it open back up and flood it with
> epoxy, then pull it shut and leave it for a day or so before raising
> tension.
> Fenton
>
> ----- Original Message -----
> *From:* paul bruesch <paul at bruesch.net>
> *To:* Pianotech List <pianotech at ptg.org>
> *Sent:* Thursday, February 28, 2008 7:12 PM
> *Subject:* Pinblock separation
>
> I was doing what started out as a 35c pitch raise today on a 1969 S&S
> console. Room was 71F and 15%RH. Musical, elderly owners.  About in octave
> 5, I heard a kinda thunk noise that sounded like it came from below. Removed
> knee board, looked around, saw nothing amiss near as I could tell.  Then
> noticed the crack between the pinblock and back at the far bass end. At the
> time, I wasn't in the habit of checking for such things prior to starting a
> tuning (my really bad bad) so I'm not certain whether it was there before.
> (Yes, I'll be checking that before EVERY tuning from here on out!)
>
> Decided to press on.
>
> Discovered that the notes I'd just tuned were very flat, and the 35c I'd
> been pitch raising now was more like 80c.  As I completed my PR pass the top
> 6 or 8 notes were close and required very little overpull. The low bass was
> also still close, but flat.
>
> Could this fairly short and narrow (about 12" x < 1/16 at widest point)
> separation have that dramatic an effect? The separation did not change from
> the time I first noticed it until I left after speaking to the owners (at
> least 1/2 hour.)  Could the thunk noise have been something else that would
> cause this? I think cracked plate, but from all the reports I've read here
> that is more like a shotgun blast. This thunk was like dropping a 4" piece
> of 2x4 onto the bottom board.
>
> Thanks,
> Paul Bruesch
> Stillwater, MN
>
>

Hi Paul,

I don't know what the noise was but I doubt that the seperation in question
is the cause of the tuning problem. I have fixed many seperations of that
type and I have never, ever, ever, lowered pitch to do so! Just clamp it,
pipe clamps NOT c-clamps as close to the screws as you can get and still
have working room. Drill through the piano for Carriage bolts to be inserted
from the back, 7/16" if there is room 3/8" grade 5 hardened if not large
washers under the head of the bolt small flat washer and lock washer under
the nut inside. Epoxy if you wish, I use Titebond yellow glue. My rule of
thumb is to bolt the entire piano, if you have a seperation in one section
it will eventually spread, you are already there with drill, clamps etc. do
the whole thing and be done with it. I'm short on time this AM if you are
going to do this I have other tips & tricks for you, just let me know.

Mike

-- 
We have enough youth, how about a fountain of SMART?
Michael Magness
Magness Piano Service
608-786-4404
www.IFixPianos.com
email mike at ifixpianos.com
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