[pianotech] Pinblock Separation

[Wesley Hardman]

This is very good information, and I am very appreciative for it.  If these
people decide to have the piano fixed, I will make use of the information
you have provided me.  I will say that the manufacturer I had reference to
earlier was Steinway.  I've never done one of these repairs, but a member
of my chapter found one of these cracks on a Steinway 1098;  he called the
manufacturer;  the rep told him that it would not affect the tuning of the
instrument;  the member has been tuning this piano for years and has yet to
make the repair.  As I said earlier, the Kimball studio pinblock separated
from the frame this past weekend while being played, and the cracking
process was very audible, resulting in a very out-of-tune piano.


On Fri, Jan 11, 2013 at 7:26 AM, Jon Page <jonpage at comcast.net> wrote:

> I've done this many times. The tension does not need to be let down. You
> do need many industrial strength clamps. I use hand screws and pipe clamps.
> Draw the crack closed with the clamps. Remove a screw and drill thru for a
> 5/16" bolt. A carriage bolt could be used but I have found the the soft
> face board on the back allows the bolt head to crush into the wood too
> much, so I use hex head bolts with washers. 3/8" bolts if more force is
> required.
> You could use T-nuts but they are pricey and chances are that your local
> hardware store does not supply enough.
>
> The reason to close the gap first is two fold. First, to prevent drilling
> debris from impacting into the gap, thus preventing its closure. Secondly,
> if the bolt hole were drilled prior to closing the gap then the holes on
> either side of the separation will no longer be in straight alignment once
> closed and the bolt itself will restrict closure.
>
> Many times glue is not needed for shallow separations. If glued, leave the
> clamps on overnight after all the bolts have been installed.
> Also, if the top is loose, bet that it is separated along the bottom as
> well. Check the bridge apron/body glue joints while you're at it. It's also
> good time to check the bridge notch at the treble break strut. Many time
> the bridge is touching the plate. Cut the bridge free with a saw blade
> drawn against the plate to recess the bridge. Might as well lube the
> casters while its on its back....
>
> -- Regards,
>
> Jon Page
>
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