Hi all,  I've been somewhat following the cracked plate discussion,
so I thought I'd add my $.025 here.  At a PTG meeting years ago, one
of the senior techs/craftsmen there brought up the subject and told
a tale of that very thing happening during a pitch raising of greater
than a 1/2 step in an afternoon pitch raising/tuning at a Catholic
school where he regularly tuned their pianos (this one had been
recently donated).  This was due to the fact he was called away from
his job by the Mother Superior.

I still own a 1925 Gulbransen player with a cracked plate (really
common with these).  I drilled a hole at the cracks terminus to prevent
further travel, and in 16 years it has never cracked further or caused
any problems.  I tuned another Gulbransen with the same crack, did the
same thing for it, as far as I know, it's still good, and that was
years back as well.  The 1925 Gulbransen plate was prone to cracking
near the nose bolt on the bass side of the plate; I found documentation
for that back then when I discovered the problem.

I haven't yet had a catastrophic plate failure in the years I've been
tuning, and pitch raised way too many old pianos to count any more.

Dan Armstrong - Armstrong Piano Tuning & Repair
Pine River, Minnesota