>While we're on the the topic of centerpins....has anyone come up with an
>explanation for why some centers tend to freeze up (I believe the
>offending pins were identified as being the German silver variety)? A
>scientist here in Champaign had an explanation that seemed reasonable.
>I'm trying to locate him for a quote... Anyone care to take a stab at it?
I've noticed that often the way to get potential freezing hammer shank
centres to seize on grands is to dust the knuckles with pure talc. Any talc
that gets into the bushing area will seize them up almost instantly and
completely.
This happens particularly often on Yamaha and Kawai pianos, and I've noticed
that often the pinning is "backwards", ie: the pin is tight in the bushing
and loose in the wood. It appears to me the talc gets into the wood and adds
enough friction to seize the pin. If the pinning is correct this doesn't
seem to happen and it doesn't seem to happen again after repinning..
On the other hand, I have a Chickering grand I look after where the pins
seize all the time, even after repinning. On this instrument it appears to
be contamination of the bushing cloth somehow. I have since lubed it with
CPL (the new stuff) and it seems to be much improved. This seems to be
unrelated to the Asian piano problem though.
Just a thought...
John Musselwhite, RPT - Calgary
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