Ric, you are right the difference is small when only removing WW but much more so with assist springs, which I may have mentioned in my previous posts on the subject. Is it as much as other removers/affecters? no. Does it (use of springs) cause an atypical feel from that loss of friction and less break away resistance (with less lead/key mass)? yes. As for Nordic you have only to ask. C ----- Original Message ----- From: "Richard Brekne" <ricb at pianostemmer.no> To: <caut at ptg.org> Sent: Sunday, October 21, 2007 5:10 PM Subject: [CAUT] lighter touchweight > Hi Chris > > Grin... dont really see what you are apologizing for, but let go. Your > posts have been thought provoking and well thought out seems to me. > I've heard about the class you refer to and hope to run into this one on > one of my infrequent visits stateside... HEY !... perhaps we can get you > two to do the Nordic ? :) > > I still dont really see clearly how we are going to see a significant > reduction in friction at the capstan/knuckle interface if all one is > doing is removing a couple grams of weight there... much less if all one > is doing is keeping the existing weight on the capstan but changing how > much each of the two top action components individually contributes to > that weight. > > Even up at the top where the weight on the capstan can easily get as low > as 70 grams... a subtraction of a couple grams of whippen weight only > reduces the total weight at the capstan by just under 3 %. And in the > bass the total weight reduction would only be about 1 %. > > I can certainly imagine how dropping the weight at the capstan by the > total amount of whippen radius weight (using assist springs) might > significantly affect friction there, but then you are reducing weight at > the capstan by significantly more in that case. About 25 percent in the > above example... and say around 10 % in the lower bass. Still... seems > to me the bulk of friction in the action is to be found elsewhere. > > In your looking into all this, have you and Don tried simply removing > the hammer all together and attach comparable weight to the jack top to > see what friction change there is in a <<with knuckle/jack friction and > without>> scenario ? > > Cheers > RicB > > > I apologize Ric. To do this more"scientifically" you should of > course remove > lead from the key before/after hooking up the spring or after removing > weight from the wip in order to maintain a constant BW. This is > something > Bob M and I discovered in our class recently in Oklahoma. We now use > models > to teach these principles, made by the Florida State piano > technology grad > program, with exchangable shanks having 15, 16 & 17 (10) mm knuckles > (constant StrikeWeight), movable captstan boats, asssist springs, easily > removable and replaceable leading, and we also introduce the cut > punching > and balance rail shimming techniques. Used to be hard to get these > things > across but thanks to the models we have arrived at a real method for > teaching these concepts. And we are discovering additional benefits like > "wow where did that additional friction reduction come from?" > > I agree with you, it must be a slightly higher Ratio than we would > like for > a happy marriage with the SW, but it appears nothing is to be done > on this > account. It has, however, provoked some interesting discussion. > > See ya on the web, > Chris Solliday
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