Paul, There is no need to guess about friction - there is an easy way to tell what the total friction is in a particular key. Subtract the upweight from the downweight and divide by 2. That's your total friction. If it is above 15 gm., that's too much. If it's below 10 gm., that's too little. If the problem is friction, and all the usual culprits have been taken care of (keypins, flange bushings, capstan polishing, etc.) your excess friction is could be in the capstan/wippen interface. This is where the whippen to capstan angle can make a big difference. If the problem is parts weight, Fred's advice to reduce the hammers will work to a point. If we say that your action ratio is around 1:5+ or so, reducing one gram at the hammer will reduce the weight by the 5+ grams at the key. It's pretty hard to lose more than 1 gram at the hammer... We here at SFSU have partially "rebuilt" about 6 Steinway actions of all vintages with whatever wippens are available. We get used wippens from a local rebuilder and recondition them - because new ones just aren't in the budget. I have several times used various sample parts kits and whatever spare parts I have lying around to run comparisons, and different parts combinations (including the knuckle positions) make noticeable touchweight differences. I think I have some data here in the office somewhere... Ah yes, here it is. Now let's see if I can interpret what I wrote down years ago... I have data for 3 pianos, but only one of them has the parts names (all the other ones are notated in Renner parts numbers - and I don't have a catalog or a parts list here at school). So let's start with the Steinway L serial #430355 (can someone look up the date and the parts vintage?) Notation is downweight/upweight, friction. Original parts: 58/31, 13.5 Steinway NY Improved wippen with original shank 53/29, 12 Steinway NY Improved wippen with Steinway NY Improved shank 49/28, 10.5 Original wippen with Renner Hamburg style shank (17 mm. knuckle) 48/32, 8. Steinway NY Improved wippen with Renner Hamburg style shank (17 mm. knuckle) 46/26, 10. Renner Hamburg wippen with Renner Hamburg style shank (17 mm. knuckle) 48/29, 9.5 Renner Hamburg wippen with original shank 55/32 11.5 All the shank were pinned at a more-or-less equivalent friction. I'll take the data home and I'll try to post the data for the other pianos identifying the parts used in the experiments. I have data for Steinway M #343357 and Steinway D #418477 Israel Stein Original pa >Tue, 24 Aug 2010 01:51:32 -0400 From: "Paul Milesi, RPT" <paul at pmpiano.com> >Thanks, Fred, for this reply. Your first paragraph states quite clearly what my intuition was telling me so far as the implications of DW and UP insofar as it being more of a relative weight issue (keys/hammers) and possibly small geometry changes that make old and new parts not quite compatible. I also recognized that rep springs are not in play prior to let-off, which is why I stated in my first post that I didn't think that was the source of the problem. I feel a "heaviness" in my hands/fingers when I touch the piano, and as a pianist I just know it's not right. The measurements of course bear this out. >Having said that, I don't rule out friction, and as time permits over the next few days I will re-examine critical interfaces using the very helpful input others have offered here. >I have also just located 2 NYI Steinway repetitions from the last set I put on an M, and am anxious to take them to the school and compare them with the older ones on the D, see what's up. Installing them side-by-side might yield some interesting comparisons, if everything else is equal. >Thanks, everyone, for your input. I'll keep you apprised in the days ahead. I won't have a large block of time for this piano for at least a couple days now, so there's time to mull things over, try a thing or two, etc. -- >Paul Milesi, RPT Staff Piano Technician Howard University Department of Music Washington, DC > From: Fred Sturm <fssturm at unm.edu> > Reply-To: <caut at ptg.org> > Date: Mon, 23 Aug 2010 21:22:19 -0600 > To: <caut at ptg.org> > Subject: Re: [CAUT] Down Weight Too High With New Hammers > > On Aug 23, 2010, at 2:53 PM, Paul Milesi, RPT wrote: > >> Just wondering if >> this touchweight issue is common when putting new hammers on a >> Steinway D >> from this period, and if there is a typical or common remedy or >> approach to >> solving the problem. > > > From what you have said, it appears to be a weight and geometry > issue. Those high upweights indicate reasonably low friction. Key > leading on the heavy side sounds typical and removes the option of > adding lead (though I wouldn't rule it out entirely - not having seen > what you have seen, anyway). Roger Jolly is probably right in saying > that cleaning and lubing the rep springs and grubs will make it feel a > little lighter, but I don't believe it will change downweight/upweight > (they aren't engaged during the part of key travel that is measured > for weight). The change in feel will occur at the end of the > keystroke, and can be very noticeable if there was caked grease and > crud in there. > I don't understand how the old geometry wipp can cause a difference > in weight/ratio compared to the new one, but experience seems to say > it can. After all, the capstans are touching the wipp heels at the > same point, and the jack/rep lever is contacting the knuckle at the > same point, whether it is new style or old. I guess it must have to do > with the angle at which the jack addresses the knuckle, as that > certainly does change (enough to require different thickness let off > buttons). It wouldn't seem that changing one factor - the knuckle > distance - would make that much difference, but it seems that it does. > The newer wipp has very subtle differences in things like jack > profile. This thread makes me curious to look very closely at just > what those differences actually are. > In any case, as a practical matter, the easiest thing to address > might be weight. Reduce each hammer 1 gram, and you are in a better > ballpark. Not a walk in the park, but doable (or close - 1 gram is > about the max you can comfortably remove from a hammer by re-arcing > and tapering). It does require removing and replacing all the hammers > and shanks (and re-aligning), and a bench disc sander at a minimum, > with Spurlock's tail arcing device or equivalent. Tapering can be done > fairly evenly by timing and feel (how long and hard you hold the > hammer against the sanding disc, balancing from one side of the hammer > to the other). A scale to weigh before and after. You will need to > taper into the felt area (not all the way to the crown) to get enough > weight reduction. > If it weren't a Steinway, I'd look at a quick geometry change using > split balance punchings. But it is a Steinway, so no soap. At least > not that I know of. Maybe Ed Sutton's idea about shimming the wipp > would work. Worth the experiment. > Regards, > Fred Sturm > University of New Mexico > fssturm at unm.edu > > > > > -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://ptg.org/pipermail/caut.php/attachments/20100824/bc0ccc1d/attachment.htm>
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