Bolt strength

[Farrell]

Right you are Del. I left about a 1/8" gap or so after cranking down the
clamps just as tight as they would go with hand (and a little wrench action)
torque (and after cleaning out all debris I could get). West System epoxy
thickened with their high-density adhesive filler finished things up (just
use the plastic spreader to mush it into the gap. I also used a piece of
thin dowel to push the epoxy way down deep into the gap as far as I could -
quite sure I got it down to the base of the pinblock.  I just scraped off
the squeeze out along the top before it cured. This one had a piece of felt
covering the block, so the next day, after removing the clamps, I just
goobered on a new piece of felt to cover all evils.

Terry Farrell

----- Original Message -----
From: "Delwin D Fandrich" <pianobuilders@olynet.com>
To: <pianotech@ptg.org>
Sent: Friday, September 21, 2001 12:17 PM
Subject: Re: Bolt strength


>
> ----- Original Message -----
> From: "Farrell" <mfarrel2@tampabay.rr.com>
> To: <pianotech@ptg.org>
> Sent: September 21, 2001 4:19 AM
> Subject: Re: Bolt strength
>
>
> > .... I did a Baldwin Hamilton a while back with a 1/2" to 1" separation
> > across the entire back. It was a lot of work bringing it back together
> with
> > the ten clamps - and that was with tension down two full steps, and I
did
> > not quite get it completely back together - but at least the damper were
> > rising from the strings (that was the original complaint from the
> customer -
> > the plate was so bent over, the dampers were not able to lift from the
> > strings!).
> >
>
> Your use of multiple clamps is well advised. Many vertical plates are
rather
> weak along the top of the pinblock. Too much clamping force in just one
area
> could be a problem--as in a broken plate.
>
> You'll rarely get one of these things all the way back together. The
longer
> the gap/separation has existed, the harder this will be.
>
> Which is why you use a combination of bolts and adhesive to hold them once
> you give up on the notion. It's also why I use epoxy. In the end, when
> everything is cured, I can grind off the excess and at least it looks like
> there's no gap left. Ron's point is well taken, though. Titebond will
> generally do the job and it's much less messy. And, if you're concerned
> about leaving a visible gap, you can always shim the thing.
>
> Del
>