Diane DeTar stated that some Gulbransen pianos will break the plate
near the bottom.  The reason for this, is that these brand of pianos
(especially the cheap commercial grades) have very nasty habit of the
bottom screws pulling loose.  In almost every example I have rebuilt,
the bottom screws are stripped, letting the tension bend it forward.
It may remain in that condition for years, until some tuner comes along
and pulls it up without checking the screws, and then Boom! you have
scrap piano parts!

These pianos are now almost 100 years old and we have to change our
approach to servicing them, by expecting new things to fail we have not
thought about before.

I was asked to tune a Gulbransen the other day.  Upon opening the top
I saw that the plate was bent in a forward arc near the top, plainly
visible.  It turns out the pinblock had pulled forward from the rear
beams.  I refused to tune it until it was repaired.

Most piano plates are made sturdy enough to do the job, or it could
not be a piano at all.  The wood securing the screws will fail far
before the plate will.  If a plate has failed it is rarely due to
improper casting.  There has to be something that has changed position
since it left the factory, putting it in a strain or bend.

Andy Taylor