Frame Cracked Twice, Engineering help?

[Roger C Hayden]

To those who are curious:

I'm persuing the locknstitch method.  I've talked to them in Calif. and
they want pictures.  The method for me is to cut out (saw out) the crack
and heat affected area, make a steel 'plug' to fit back in, and metal
stitch it back together.  Stronger than original.  They are using this
method on pianos already.

Gary, my contact, has already taught Pianotechs out there on the left
coast, and was invited to teach it at the Nat. convention in Arlington
but couldn't schedule it this year.

We're on to something!!

Thanks for the tip, Greg

Roger Hayden, RPT

On Tue, 21 Mar 2000 09:12:11 -0800 Greg Granoff <gjg2@humboldt.edu>
writes:
> 
> 
> Roger C Hayden wrote:
> 
> > OK, Guys, I need help
> >
> > Hazleton Bros. 5'10"  Grand.  Neatly rebuilt, (by me).  Too little
> > downbearing in the treble, so I lowered it a bit.  (I've Done such 
> things
> > before.)  Brought up the tension nice and evenly, installed 
> dampers,
> > sounding good at A-440, ready for fine tuning.
> >
> > During the Fine Tuning:   THWUNK !!  I couldn't see anything, so I 
> played
> > a chromatic scale.  It climbed nicely until I passed the last 
> strut, and
> > dropped a fourth.  Then I could see the crack, travelling toward 
> the
> > Northeast, but holding near the edge of a circular sound hole.  I 
> QUICKLY
> > dropped tension on that section, and then dropped the rest of the 
> piano.
> >
> > Fortunately this pinblock is only attached to the frame, and not 
> to the
> > case, so I loosed everything, pulled out the frame with the block 
> and
> > strings intact, and called a welder who assured me he could handle 
> this.
> >
> > Re-painted, reinstalled, strings back in place, tension up to 
> A-440 and
> > holding.   Last Friday before bed I played a chromatic scale 
> again, and
> > it wasn't chromatic. . . . . .  So I dropped the tension on the 
> last
> > section and went to bed.
> >
> > There's more to welding cast iron then I knew.  My welder did not 
> heat
> > the plate, nor cool it slowly, as I hear is necessary.  And I've 
> heard
> > from a far more skilled fellow, that this kind of welding is very 
> much an
> > art.
> >
> > Question:  What if I had a steel plate created, and with PC-7 
> between it
> > and the underside of the frame to give it strong frictional 
> contact,
> > drilled, tapped and bolted  this plate in place below the cracked 
> area.
> > It would be out of sight, and providing considerable strength for 
> that
> > area.  Would this be sufficient to bear the tension and give us 
> our whole
> > piano back?
> >
> > Roger C. Hayden, RPT
> > Clarks Summit, PA
> > ________________________________________________________________
> 
> Roger,
> I've included a link to a site which promotes an intriguing and 
> apparently
> extremely successful
> variety of cast iron repair.
> Haven't talked to them, but I understand that they have done piano 
> plates and
> consider their procedure highly appropriate.
> It might be worthwhile to check with them, regardless of what you 
> ultimately
> do.
> Good luck!
> 
> Greg Granoff
> 
> Here's the address:           http://www.locknstitch.com/
> 

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