bare bridges

[Robert A. Anderson]

I, too, encountered a "bare bridge" piano last week - a 20 year old
Bechstein grand. The others I have seen have all been European. I think
it's a matter of style. I've heard one opinion to the effect that the
graphite serves as a sealer to the surface of the bridge, rather than
acting as a lubricant. In a PTG Institute class in 1985, Klaus Fenner
stated that a string had to be pulled about 60% of a semitone before it
broke the friction at the bridge. I don't remember if he commented on
the efficacy of graphited bridges. I wonder what the difference in
friction is between plain wood and graphited wood in this application? 
Perhaps someone is interested in conducting an experiment. Intuitively,
it doesn't seem like there would be that much difference.

Bob Anderson
Tucson, AZ