Pinblock/Frame Separation

[Farrell]

Thanks Jim, I will have fun.  However.............."and the plate has not
cracked (can we agree on this much?)". Well, I have a bit of concern that
the plate could be broken right now (prior to repair) on the back side at
the bend. Then when I pull the plate back toward the frame, the front of the
plate at the bend will open up!  It's kinda scary! I think Newton has a
point - cast iron can bend a bit over a large area, but can't bend much over
a small area. My area is small and it has a big bend. I think there is a
reasonable chance that it is cracked on the back side right now.

Terry Farrell
Piano Tuning & Service
Tampa, Florida
mfarrel2@tampabay.rr.com

----- Original Message -----
From: <JIMRPT@AOL.COM>
To: <pianotech@ptg.org>
Sent: Thursday, July 27, 2000 5:45 PM
Subject: Re: Pinblock/Frame Separation


>
> Well lets look at this from a fifth perspective......., i.e., the plate
and
> block were at one time attached firmly to the backframe and it did not
crack
> in that position......it has migrated to the present position of
block/back
> seperation and the plate has not cracked (can we agree on this much?)
Given
> this set of parameters, pulling the plate/block back into position 'should
> not' cause the plate to crack. After all, the plate is just going back to
a
> position it has already been fastened in and returning it will impose no
> extraordinary stresses to which it has not already been subjected.
> (keeping in mind that the piano is said to be overly flat already)
>
>  Now without regard to whether the downbearing is affected by this plate
> shift, either way, the plate and block need to go back as close as
possible
> to the factories positioning, unless you desire to go into rescaling and
> redesigning. I don't think I would bother doing that with a model 243.
>
>  Doing this repair is simple from my viewpoint.
> 1. Clean out the crack as well as is humanly possible. (use your favorite
> method)
> 2. Using your favorite type clamps pull the back/block&plate back together
so
> that the crack is as reduced in size as possible.
> (using too many clamps is a virtue here so as to spread the pressure on
the
> plate widely..... pressure should be applied to each suceeding clamp a
little
> at the time rather than trying to snug one little section up as tightly as
> possible before going on to the next one. Alternating tightening works
well
> for me.)
> 3. Take out the screws holding, or not holding as the case may be:-),
> everything together at the top of the plate, typically there will be 5 or
6.
> 4. Using your favorite size drill thingee drill a hole completey through
the
> block and back assembly from the FRONT side.
> 5. Insert the proper sized 'carriage bolt'/washer combination from the
back
> side and install a washer and nut loosely, that means don't snug it up
yet,
> from the front.
> 6. After all bolts/washers have been installed loosen each nut so that it
is a
> prox three (3) full turns (depends on tpi) away from the plate.
> 7. Loosen each clamp a little until most of the pressure is off the
clamps,
> the crack has reopened and the nuts are helping hold the plate/block.
> 8. Pour/squeegee/spatula your favorite adhesive down into the crack.
> 9. Reapply pressure to the clamps and draw the crack back together a
little
> at the time. (patience counts here and it won't take any longer)
> 10. When the clamps are as tight as you feel needful, tighten down all the
> nuts.
> 11. Allow your adhesive of choice time to set up and remove clamps.
> 12. Tune the thing and collect your well earned fee.
>
> Using the Nossaman method I left out all of the common sense stuff like
don't
> drill a hole in your hand or finger, don't clamp your pinkie too tight,
don't
> glue action parts together, don't make a mess and clean up the mess you
make,
> etc.... :-)
> Have fun, Terry.
> ©Jim Bryant (FL)
>
>