[CAUT] Touchweight, etc.

[Fred Sturm]

On 7/31/05 2:05 PM, "James Ellis" <claviers@nxs.net> wrote:

> I deal with the friction first.  Keys first, absolutely, before anything
> else, then the various action centers.  There is no sense fretting with
> action centers if the keys are binding.  To do a thorough job checking the
> keys, the stack must of off.  You will find things you can't find if the
> stack is on.  After you have the keys all in good shape, deal with the
> action centers.  Don't overlook mundane things like rep levers rubbing on
> adjacent knuckles, and stuff like that.

    I agree with Jim Ellis 100% on this. Don't even look at weight until you
have examined friction, particularly key friction (and then alignment
issues). For key friction, yes, the stack must be off. To check the keys
thoroughly, use lead counterweights on the backs of the keys. A couple jiffy
leads, and a couple half jiffy leads, will serve very well. Place them on
each key in turn, enough weight and placed so that you counterbalance the
key leads, so that the key is balanced and doesn't want to go one direction
more than the other. Then nudge the key in either direction (down in front,
down in back). It should move freely - float. There will be a difference in
response from bass to treble, due to change in mass, but it will be obvious
which keys have friction issues, and you will see much more than can be
found by other means. Even tiny amounts of balance bushing or balance hole
friction will show up in an obvious way.
    This goes pretty fast, as the number and placement of weights will (or
should) change very gradually as you go up the keyboard (a bit of difference
from sharps to naturals). You will also see where keys have been weighted
unevenly. If that is the case (and it nearly always is, at least to some
extent) mark the keys that are unevenly leaded, and consider just removing
an obvious lead or two where that seems appropriate, before your later,
finer leading work. (If it's really haywire, do a pattern leading, but
that's another topic). Unfortunately, the key weighting folks in most
factories are not well trained, and lack curiosity - they solve all problems
by adding lead. This seems to be true in most factories to a greater or
lesser extent, and many rebuilding shops are also guilty.
    Once you have addressed key friction, and looked closely at
alignment/rubbing issues - visually making sure there is no contact of
hammer felt, knuckles, reps to neighbor knuckles, etc. - a quick check of
other friction is simply to do a quick upweight check. Use a 15 or 20 gm
weight, quickly along the keyboard, marking any that don't raise the weight
readily. Then examine those notes and find out why.
    Doing this quick and efficient work ahead of time will save lots of time
fussing and puzzling later. It's like doing the pitch raise ahead of fine
tuning.
Regards,
Fred Sturm
University of New Mexico