Rep. Lever Springs

[Sy Zabrocki]

Why are so many piano makers still using the butterfly type rep. lever
spring? The other kind is sometimes called the Schwander type (Sch). It
seems logical to me the Sch type would be superior to the Steinway type
butterfly. Look in the piano supply catalogs to familiarize yourself.

The butterfly is more difficult to adjust because you have a bend the spring
by trial and error. The spring may or may not be dirty or corrided which
causes friction. Ocassionally they can even squeak. I guess I would almost
call it archaic.

The Schwander type uses a spring attached to the low end of the rep lever.
The other end of the spring extends toward the jack and hooks with a loop
into the jack. There are several variations as can be seen in supply
catalogs. The Sch type is easy to adjust and there is no, or at least very
little friction. It just seems logical it is superior to the butterfly.

Early Yamaha, Kawai and Samick (maybe others) all used schwander type at one
time and all now use the butterfly. As a Kawai dealer up to about 1988 I
pointed out to my customers the schwander type whippen as a PLUS  FEATURE. I
really believed it to be true. Then about 1988 Kawai changed to butterfly.
My sales rep didn't know why for sure but mentioned tests had proven the
butterfly to be faster. I just can't reason it out why the butterfly would
be faster.

Both springs when properly adjusted support the knuckle, shank and hammer
when at rest. Now suppose let-off has occured and the hammer is at back
check. Observe that the rep lever is now depressed not more than maybe 3/16
of an inch (more or less). As the key is released the lever raises the
hammer and the jack returns under the knuckle. Here it the question. What is
there about the butterly when traveling such a short distance that would
make it faster? If the butterfly is faster what is the factor that doesn't
seem obvious. Someone enlighten me please.

I suspected all these makers even changed to butterfly just to emulate the
big "S" (Steinway). Maybe it had something to do with sales. What do the
German makers use? The Renner catalog shows some of both. Is it the Shimmel
that uses the butterfly but has an adjusting screw. Now that's my kind of
whippen.

In my daily work I don't regulate grands as often as maybe the university
technicians. But let me tell you, adjusting the spring tension by bending
that stupid spring is not my most enjoyable hour (or hours). I'm always
wondering about the friction and is it clean. I'll adjust the schwander and
whistle a tune while I work.

One can be reluctant to post when there a possibility you might end up
looking stupid. I'm about to turn 65 after 38 years in this work I don't
care. If I'm still stupid, so be it. I can still teach and I can still
learn. I really want to hear from some of your about these springs. Does
anyone know about tests on this issue?

Sy Zabrocki (Billings, MT)
only4zab@mcn.net