II. THE TOP ACTION (off the keyframe) - continued
22) Clean repetition spring and groove (Steinway, Yamaha, Bosendorfer). On Steinway, Yamaha and the Bosendorfer whippens (which have the butterfly type repetition spring), the spring grooves are coated with a graphite solution. The Yamahas now use a teflon coating here, but the older models of this type whippen are graphite.
Hurray that someone has finally seen the light! This graphite paste becomes dirty and gummy, and makes for a source of friction instead of eliminating it. These grooves in the underside of the balancier and the spring tips must be cleaned in order to achieve a good regulated action. If left uncleaned, the jack height is very hard to set since the repetition spring not only has to support the knuckle, but also has to overcome this messy graphite paste as the balancier moves.
To clean this groove, release all 88 repetition springs from the grooves and turn the action upside down, taking care to protect the hammers while doing so. Run a piece of cloth up and down the grooves until clean. Be careful not to damage the groove. Now choose a lubricant which will, hopefully, eliminate this problem during future use. I have tried three different lubricants for this job, but I have reservations about all three of them. If any of the readers have a sure-fire method to solve this problem, please be kind enough to share it!
I have tried:
1) Dag 154. This is a graphite solution and works well for lubricating the spring. I question whether it will be free from the dirty, gummy mess which plagued this area in the first place.
2) Spray teflon. I feel that this teflon is not as good as what is available to the manufacturers. It does not seem to last. Hence, the repetition spring, while not getting dirty and gummy, will also not be lubricated quite well enough.
3) White grease. This is supposed to prevent rust and corrosion on the spring. It is not absorbed into the wood, but it is bound to get dirty with time. As to whether it will also get gummy and inhibit the spring is anybody’s guess. The ideal would.be to apply a teflon coating like what Yamaha now uses, but to my knowledge this is not available to technicians.
Turn the action right side up and clean the tips of the repetition springs with a suede brush. Rebend the springs back into their grooves, making sure that the spring is indeed in its groove by applying as light sideways motion.
23) Round whippen felt if needed. The cushion felt on the bottom of the whippen which rests upon the capstan always compacts and gets worn from the constant hammering of the capstan hitting against it. Incidentally, this compacting along with the flattening of the knuckle is why a new piano always loses its hammer line. In the case where these parts have only “settled in”, the action can be brought back into regulation by raising the capstans and making the corresponding adjustments in the let-off and drop. Since raising the whippen puts the jack tender closer to the let-off button and the balancier closer to the bottom of the drop screw, these two must be changed.
I use two wear areas, the knuckle and the whippen felt, to decide whether to repair an action or to replace the action parts. Just like a flattened knuckle, a worn whippen cushion felt must be ...
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