[pianotech] Vertical Touchweight

[Floyd Gadd]

List,

I enjoyed the discussion about the Crescendo punchings, but since I didn't
get much feedback about my questions of touchweight targets, I decided to
weigh off a Yamaha piano of similar dimensions to the mid-60's 41 inch
Heintzman I am working on, and see what I could learn.  The Yamaha is an
LU-101 I purchased in 1984, and I've always enjoyed the feel of it.  I noted
that none of the sharps had lead weights, though the naturals did.  This
piano ran near the bottom of the product line when it was made, so I'll
assume that the weighting was more or less standardized rather than
customized for the individual instrument.

I'm attaching a chart of my results.  Here are my generalizations on what I
found.

>From A0 to D2 downweight averaged 55g, upweight averaged 35.6 grams, balance
weight averaged 41.5 grams and friction averaged 9.7 grams.

>From D#2 to F#3, downweight sat right around 50 grams, and upweight averaged
36.6 grams.  Friction ran for the most part between 6 and 8.5 grams.

>From G3 to E6, downweight for the naturals hovered between 44 and 47 grams,
while the sharps came in between 47 and 50.  (I assume the difference was
incidental to the manufacturing process, not deliberate.)

>From F6 to C8, downweight fell pretty consistently at 49 to 51 grams.

Single digit friction was the order of the day, with the exception of 7
notes in the low bass.  Only rarely did friction come in as low as 5
grams -- 6 to 9 was typical.

As I prepare to rebalance the Heintzman keyboard, here are my proposed
targets for downweight:

A0 to D2 - 55 grams
D#2 to F#3 - 50 grams
G3 to E6 - 48 grams
F6 to C8 - 50 grams

I will monitor friction as I go, but given all the work I've done on
flanges, key bushings, and overall lubrication, I expect to see fairly
consistent measurements.  I'll let upweight fall where it will, but will
record the results.

I'm really curious to find out how the Heintzman will feel when I'm done.

Any comments?

Floyd Gadd
Manitoba chapter

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