Conover Plate cracks

[Jim Coleman, Sr.]

Hi Richard:

You may have just become the worlds expert on Lock-N-Stitch as far as
piano plates are concerned. Whatever type repairs you use for the rest 
of the job may be incidental in comparison to the job of carefully fitting
the pinblock panels to the plate. Traditionally, pinblocks get lamp-black,
blue chalk, red chalk or some material which will be offset from the plate
surfaces to the block as indications of where to relieve pinblock material
to facilitate a good close fit everywhere. To make these imprints on the
block, apply the chalk or whatever you use to the plate at all places where
the pinblock will be touching the plate. Then, place the pinblock against
the plate and tap it with a hammer to imprint the chalk on the block. Remove
the block and you will see all the places where the block was not in contact
with the plate. Use a rotary rasp or plane to rasp off the areas where the
color did imprint the block, then try it again, and again until the material
offsets almost completely to the block. This will insure that you have a
good intimate fit between the block and the plate. Then when you screw the
block to the plate, you will not as likely create any stresses between the 
block and the plate. When you fit the continuous 1/2" pinblock material 
which ties the 3 or 4 pinblock segments together, you will also want to make
sure that this strip does not force some warp. I think I would epoxy this
strip to the individual blocks so that in the future the block can be 
removed as a unit. If this last seems strange to you, perhaps I misread your
previous posts describing your layout.

Jim Coleman, Sr.


On Thu, 7 Jan 1999, Richard Snelson wrote:

> I would like suggestions and ideas on how to repair the following:And
> your thoughts on how I'm currently going about it.  
> Piano: Conover 1908 6' Grand. The piano had four individual pin blocks
> seperated by three webs in the plate. The pins blocks are open on top
> with no web covering. On the bottom they are tied together by a single
> maple 1/2" thick cap that holds the whole pin block together. The two
> 1/4" thick webs in the treble section are cracked one completely from
> top to bottom and the other half way up. Piano case is beautiful walnut,
> sound board is in good condition, action in fair condition.  
> 
> Looking carefully at the tiny amount of evidence available, it seemes
> the piano was repaired for this problem in 1928 at the Cable Factory in
> Chicago (Signed/dated by the worker on a string support wooden piece).
> This is based on the weld flanges used to repair the webbs and the cuts
> made at that time in the seperate pins blocks that had been out of the
> piano. The cracks were not showing when I obtained the piano but did
> after I removed the plate. I understand the welds failing because of the
> hardness of the cast iron on each side of the weld. Sloppy work on my
> part, in lifting the plate at the back edge with out support on the
> front edge which was stuck, no doubt cracked the welds loose.
> 
> The web starts in the vertical direction 1" below the pin blocks top
> surfaces and extend about 1 1/2" above the pin block. The part at the
> very bottom edge that had been welded was  narrow 1/8" and this is where
> the crack had started.  I think this is a basic design flaw in the
> casting. 
> 
> I have repaired one crack with Lock-n-Stitch and will do the other
> partially cracked webb next. I don't have a lot of faith in the
> Lock-N-Stitch. I will address this to the list if there is interest in
> how to complete a Lock-N-Stitch repair. It can be tricky! I have cut the
> 1" webb that extends between the pin blocks off completely and have
> designed a 1/4" steel truss to go in it's place. It will be bolts to
> each side of the area, front/back with aircraft bolts. 
> 
> I understand the thinking of those that will say "junk it now." You are
> no doubt correct. However, I need a project for my own education. I'm
> thinking of completing the plate repair. (With your inputs to help) 
> Spray painting the plate/making new pin blocks. Installing the plate,
> stringing the piano and bringing it to pitch. If it's OK at that point I
> would leave it for a while before lowering the pitch, and again removing
> the plate to do all the refinishing on the sound board/case etc. I don't
> see a problem with removing the plate with the srings in place, I'm the
> new kid on the block at this, so is this correct??  
> 
> Some of my Questions: What do you think the load is on the webs?
> Are they in tension? 
> Small to almost no load? 
> Anyone had luck with brazing cast iron? 
> 
> 
> 
> Oh by the way, I would keep the piano for myself and not pass it off to
> some unsuspecting customer. My wife loves the ornate walnut case. 
> 
> Richard Snelson 
> Clinton, IL 
> Phone: 217-362-7432 days   217-935-4215 eve.
>