Ana Gerard asked about grand pianos that used brass flange whippen.
I have a Chickering, Scale 123, 6' 6" (about 1900, don't have the
serial # in front of me) that has Billings brass flange whippens
and Billings brass flanges on hammers.  I had the same Chickering
in a 1904 model in which only the hammer flanges were brass.

I have the same scale Chickering in a non-production-line art case
Ampico (1922) with wood hammer and whippen flanges.  Don't know at
what precise point/time Chickering abandoned the Billings flanges,
partially and completely.

Gary Bagley