Hey Sarah and all, Just read your post and a few others, to many on this thread to read all.... (and still get my daily work done) A few comments: Steinway used to specify both up weight and down weight for each key and by this they specified the total friction in each key. They had lots of different specs but in on average they tapered Down weight from 50 to 46 grams and up weight from 20 to 24 grams. This translates to a uniform Balance Weight of 35 grams and a Friction Weight tapering from 15 to 11 grams. Years ago I experimented extensively with adjustable friction flanges of my own design using a 0-80 hex bolt that put pressure on the top of the hammer flange bushing cloth. I found that when I set the Balance weight to 35 grams and adjusted the friction nuts so that up weight tapered from 20 to 24 the resulting in down weights tapered from 50 to 46. The resulting flange frictions, measured at a radius of 32mm, are always around 5 grams (as long as the key bushing are free). The swings with a top medium hammer weight are usually something like 5 swings in the bass tapering down to 3 swings in the treble. So this supports the application of a uniform rotational hammer flange friction of around 5 grams, based on traditional Steinway Specifications. The lowest friction imaginable is achieved with the Rolling knuckle which has been used on some Steingraeber pianos. I spoke with pianists who played on the first prototype, displayed at the German Piano Tuners annual meeting a few years ago. The word from the pianists who played the roller demo at the meeting were not positive. BTW I measured a model in Nashville with a rolling knuckle. The D/U was 56/33 with a Balance Weight of 44.5 and a Friction of 11.5. Then I jammed the knuckle so it wouldn't rotate and remeasured U/D. The DownWt went up to 61 and the UpWt went down to 29. The Balance Weight essentially stayed the same at 45.0 and the friction weight went up to 16.0. The points I'm making are: There is historical evidence that supports the application of hammer flange frictions of around 5 grams. Pianists don't seem to desire the lowest possible friction. David Stanwood
This PTG archive page provided courtesy of Moy Piano Service, LLC