"...with special attention given to key bushing friction control." What do you recommend for key bushing friction? Minimal/near-zero without inducing slop? Some number of grams friction? What are the advantages to having near-zero and having some amount? Thanks. Terry Farrell ----- Original Message ----- > When one studies piano friction weights (D-U)/2 they find that, with > uniform flange frictions, on average the friction weight drops by about 4g > from bass to treble. This of course is due to the fact that hammers are > heavier in the bass and push the parts together with more force causing > more friction in the bass end. > > Many of us sort friction with high in the bass and low in the treble and > this exaggerates this natural tapering of friction even more. So what > you've done is to make friction weight even less tapered than normal by > putting the lower friction hammer flanges in the bass. > > One finds that a change of one gram of rotational friction measured at a > 32mm radius on the hammer flange a gram will create a difference in the > friction weight of about one gram which means a change of 1g in both down > and up weight. > > So if your sort yields say one gram rotational in the bass to say 5 grams > in the treble then your offsetting the natural decrease of friction bass to > treble of 4g with an increase bass to treble of 4g giving a more or less > uniform friction weight bass to treble so if the down weights are weighed > off to be a uniform level bass to treble the up weights will be uniform as > well. > > If, in this case, you sorted with high friction in the bass to low in the > treble the up weights in the bass would be much much slower than in the > treble, with a uniform down weight. > > If your going to sort by friction I think it makes more sense doing what > you've done because it creates a more consistent friction weight bass to > treble which in turn creates the possibility to weigh off to a more > consistent down weight and up weight bass to treble. I'm sure that many > pianists would notice and like that kind of set up. > > I actually prefer, in the case of shanks, to sort by shank strike weight > then working the flange frictions to be as uniform as can be from bass to > treble, with special attention given to key bushing friction > control. Friction comes and goes but weight is pretty constant by > comparison... > > Whew! > > David Stanwood -------------- next part -------------- An HTML attachment was scrubbed... URL: https://www.moypiano.com/ptg/pianotech.php/attachments/20060414/c60e019d/attachment.html
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