Spring behaviour

[David Ilvedson]

If I really thought it necessary, I'd use a small dab of Protek thick lube instead of graphite paste...which I don't even have in my car or shop..
Usually some micro-fine powder works just fine...I don't think we can expect this too last forever.  That spring needs to slide smoothly in the "grub" (haven't heard it called that before...;-]) any paste will attract dust and gunk up the works...IMHO!!!!

David I.





----- Original message ---------------------------------------->
From: <A440A@aol.com>
To: <pianotech@ptg.org>
Received: Tue, 22 Oct 2002 07:34:35 EDT
Subject: Spring behaviour

>Oleg writes:
>>So who will give us a good explanation on why this grease is used yet
>>originally.

>Greetings,
>   The original, and continuing reason, is to reduce the friction in the
>grub.  The graphite paste that was in use pre-1900 seemed to have used
>tallow, and it is not uncommon to see verdigris on the springs.  Later models
>sometimes have it, sometimes don't.
>   In the 1960's, the grub was coated with the synthetic green Teflon based
>stuff, but it wears through very quickly.  This period also seems to have
>softer maple wood used in the action parts, and as the spring wears an ever
>deepening groove into the underside of the balancier, it increases its
>contact area to include the sides as well as the top of the spring.  When
>this problem is coupled with the sideways bend in the spring,(which results
>from them being set in the factory from the proximal side of the action),
>the friction in these pianos gets high enough to make setting the spring, and
>all other adjustments that depend on them, difficult.  If one must regulate a
>small Teflon action as is, it helps a lot to straighten the springs
>laterally, and apply a dab of graphite paste to their contact point.
>   The major benefit of the Renner whippens is that their teflon adjustment
>screw provides a VERY long lasting spring regulation. ( I have numerous
>actions at the school where the spring adj. has been stable for years).
>Regards,
>Ed Foote RPT
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