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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