[CAUT] Gram Tension Guages

[Don Mannino]

List,

I prefer to use gram gauge specifications.

I agree with Rick Baldassin, that using swings results in added friction
in the bass.  This affects the touch, which can affect the weigh off and
inertia (depending on how you do your weigh off). This tapering of the
friction is not recommended by any piano makers that I know of.  The
weight of the heavier bass hammers already assures greater friction
(from the knuckles) in the bass, and this added friction works perfectly
to maintain control of the heavier hammers.

One can also try to taper the swings, but as Jim pointed out, this is
rather inexact, resulting in uneven friction.

When repinning an action, I get my friction spec by doing a few test
flanges in the mid treble, where the tone of the piano reveals problems
most quickly.  If the bushing cloth quality is sufficient to allow 2
grams friction on the hammer flanges in this part of the scale with good
solid tone, then this will be enough for the rest of the piano.  If the
cloth is spongy, then a tighter fit will usually sound better.

It is also good to adjust the fit according to the weather.  Pin tighter
by a couple of grams when it is humid.

The gram measurement should be of the flange while it is rotating, not
the starting friction.  When pinning to a published gram specification
you should measure at the screw hole, but for consistency it is simpler
to just measure at the end of the flange.   This takes a little
practice, but is not too hard.

Don Mannino RPT