Turbo whipping....oooh I like the sound of that!

[Fred Sturm]

I haven't dealt with the Renner turbo-spring, but have had occasion to
adjust tension on wipp helper springs on various asian models (Samick,
Young Chang, etc). I have to say, trying to weaken springs in situ
(wipps on rail, backchecks in the way) is problematic, and, try as I
might to adjust tension of the coil, I have found I mostly can't get
them weak enough in an efficient manner. So I bend them using a 45
degree damper wire bending tool. Gets in there pretty efficiently, a lot
easier than a needlenose.
	There is good reason for the prejudice against putting bends in
springs, but it mostly applies to the Steinway style butterfly, and
upright hammer return and damper return springs, which have a curved
surface rubbing against a groove. Adding a bend changes the geometry,
altering the way the curve of spring meets the groove.
	In springs like the wipp return, with a kink catching a string loop, I
can't see that it makes any difference whatever if there is a kink in
the spring wire, as long as it isn't extreme.
Regards,
Fred Sturm
University of New Mexico

Mark Cramer wrote:
> 
> "Tension has to be adjusted on a spring at the coil, as has already been
> pointed out."
> 
> Cheers
> Mark Bolsius
> Bolsius Piano Services
> Canberra Australia
> 
> Thanks Mark,
> I'll clarify the question, as you may or may not have seen the booklet Lloyd
> provides with the "turbo-wips."
> 
> Against our best judgement, the diagram shows a pair of needle-nosed pliers
> gripping the spring half-way between the coil and the hook.  The caption
> reads "place a small bend here."
-----
> 
> Mark Cramer, RPT
> Brandon University