repinning hammer flanges

[Don Mannino]

Larry Fisher wrote:

About a year and a half ago I .... I pinned all the flanges at ..... "3 swings"
.....  She had some heavy moisture problems last February ........ her remark
was "the keys were sweating" indicating that moisture had condensated on the
keytops.  After that was
when she noticed the feel of the tight pinning was gone and I was just there
today and indeed she's right.  I got 10 swings or better randomly picking
hammers in the middle of the keyboard.<<

>>Did the high humidity cause this problem?  If so, how?  (yes she has
insurance)

Why didn't the Yamaha MX100, in the same room, suffer the same problem?  [I
didn't check it but she claims it plays better than the Kawai grand at the
moment]<<

Usually high humidity causes tighter flanges. However, if the parts get wet
enough that the cloth is saturated, the bushing will be wet sized, and be made
looser. It's hard to imagine high enough humidity to make the cloth get
saturated, though! Perhaps there were temperature swings that contributed to
condensation on metal parts.

Was rust created on the strings or any other part of the piano? Did the tone of
the piano change from the hammers taking on moisture?

As for the other piano, there are lots of explanations for why it would behave
differently. First, there may have been more silicone in the bushing cloth in
the Yamaha, where Kawai uses very little if any (depends on the year the grand
was manufactured). Silicone tends to lessen the effect of moisture on the
bushing. Also, vertical actions behave and feel differently than grands when
friction is changed. Loose hammer centers don't contribute much to key bounce in
verticals. So the vertical action could have been improved by the same thing
that bothers her in the grand.

As for other causes for key bounce, this is also affected by action mass
(hammers, key leads, etc), whippen centers, keyframe bedding (back rail
especially), back rail cloth condition, hammer rebound rail adjustment, and
maybe others I can't think of right now.

Don Mannino RPT
74473.624@compuserve.com