un-weighting

[Charles Ball]

At 10:51 AM 7/23/96 -0700, you wrote:
>It's sure been quiet with ya-all at Dearborn. I'm about to begin trying to
>solve some complaints of "loose action" on a Steinway D, used for
>concerts. In speaking with the previous technician the keys were weighted
>to give it a lighter touch, after new hammers were installed. When I came
>to it, it was badly out of regulation (I'm suspicious that it wasn't well
>regulated before weighting, after a light regulation, the touch is no
>longer consistent (it really wasn't before) and the touch is predominantly
>very light. I'm afraid I need to start knocking out weights, which is a
>new operation for me. Can anyone tell me what problems I'm looking at? I
>assume I have to plug the holes. . .any details you'd like to suggest?
>
>I'm going to start out by regulating, so I won't be knocking any weights
>out today, but I'd love any suggestions ASAP.
>
>Bob Simmons, RPT


Dear Bob,

We have had to do extensive releading of keyboards at UT Music over the
years.  Often the original leading from the factory was quite uneven.
Sometimes new parts necessitated changes.

First of all make sure that you have minimized friction in the action,
especially at the knuckle and hammershank center.  Key bushings are also
very important.  This is perhaps more crucial than the regulation, assuming
that it is within working perimeters.  Do make sure that none of the parts
are rubbing their neighbors.

In general you want approximately 50 grams downweight, perhaps a bit more in
the bass and a bit less in the treble, and at least 20 grams upweight.  Look
at the leading pattern in the keys.  This will vary between naturals and
sharps, but within those groups the patters should be relatively consistent
from note to note, with a gradual decline in number from bass to treble.  In
the low bass you may find six large leads per key, while in the high treble
the leads may actually move from the front to the back of the key stick.

Consistency is very important--variations of 2 grams or more from key to
adjacent key may be felt by the pianist.  This will also affect voicing.
The upweight is also very important if the action is to repeat properly.

If you determine that you need to remove leads, start with those that seem
to have been added since the piano was manufactured.  Remember that removing
a small lead near the front of the key will have more impact that removing a
large lead near the balance rail.

It does make for a more professional job to plug any holes with a similar
material--either suger pine for a Pratt-Read keyboard or spruce for a Kluge.

It is difficult to offer a crash course on such a complex subject here, but
I truly hope that this helps somewhat.  If you have any other questions,
feel free to ask.

Charles

PS:  If you do knock out leads, take care not to split off key wood with the
leads.  The leads usually have a wide end; make sure it goes out first.
Support the side of the key so that only the lead is over a hole as you tap
it out.  Make sure that you use a punch that does not enlarge the soft lead
as you tap.  Renner sells a dandy tool for key lead extraction and insertion.

Charles Ball
School of Music
University of Texas at Austin