This is a multi-part message in MIME format. ---------------------- multipart/alternative attachment BTW: What is a wippen saddle cushion? Is that a different term for the = heel cushion? Yes, same thing. Tom Servinsky ----- Original Message -----=20 From: Farrell=20 To: Pianotech=20 Sent: Friday, August 05, 2005 6:38 AM Subject: Re: Action Balancing/Leverage Quagmire Hi Tom. Thanks for your input. Comments below: Tom Servinsky wrote: Are these original parts, except for the hammers?=20 No. Newish (few years old) hammers, shanks, knuckles, flanges, = wippens. Original keybushings with well worn key pin grooves.=20 Yes. Original wippens with excessive saddle/ capstan grooves? New. Pinning? If anything much of it is loose - what we looked at - didn't fully = evaluate. Verdi Gris? No. Too many times action geometry concerns are confused with the basics. = Excessive friction from the keybushings/ keypin relationship can affect = the outcome dramatically. My advise before any drilling and leading is = considered would be to thoroughly lubricate all contact = points...keypins, capstan, knuckles, jack tops, and even the keybushings = and wippen saddle cushions. I assure you that your findings will change dramatically. Incidentally, a tip that I picked up from my last Steinway factory = seminar was centered around this issue. The techs are now lubricating = the keybushing felt and wippen saddle cushions with Protek Pro Lube, in = addition to lubricating the keypins and capstans. The differences in = release are outstanding. Remember: measure twice cut once! No doubt, friction is an issue with this action, but the keys are = relatively free and many notes have normal friction. On the few high = friction notes we put the long-distance knuckles on, friction came right = down to 12 grams or so. So yes, friction needs to be addressed on this = action because it is erratic, but with five leads in the keys, FWs that = exceed the Stanwood ceilings, and an action ratio upwards of 7, it seems = clear this action needs a bit more than friction management. Thanks though. Some good point. BTW: What is a wippen saddle cushion? Is that a different term for the = heel cushion? Terry Farrell Hello Action Balancing Aficionados, Today I spent a good part of the day with Phil Bondi (who is = currently dodging thunderstorms along southbound I-75) diagnosing an = 1880s S&S model A 85-note action that plays like a Mack truck. Because two heads are better than one, and as we found out, they = are likely better by an exponential function, we have at least four = times as many unanswered questions as either one of us could have come = up with working alone! We actually did improve one thing right off. The drop screws were = turned WAY down to make the pathetically hung crap hammers check - sort = of. They were so far down that the rep levers were being depressed at = less than half blow. We turned them up and that made quite a difference = right away. But still, the action was sluggish. We measured upweight (UW), downweight (DW), key ratio (KR), strike = weight (SW), wippen weight (WW), knuckle-to-center distance (KC) and = front weight (FW) on all the Cs and C#s. Our objective is to = characterize what changes can be made to this action to make for a = normal to light touchweight. All results discussed herein are in grams = and millimeters. We also examined magic lines and did the measurements to calculate = overall action ration as specified by Ron Overs. The action had shanks with knuckles 15.7 mm away from the flange = center pin (is that the right distance Phil?). And it had five leads in = the bass keys and two in the trebles. The capstan/wip-heel actually intersected the magic line just = after key travel started (not too horribly bad). The knuckle/rep-lever = interface started at a full knuckle below the line and ended with the = line about half-way across the knuckle at full key depression (pretty = bad). For anyone interested in a painful experience, I will send you my = spreadsheet with all the data upon request. For those others more = sensible, but still reading this, I will summarize below: DW ranged from 49 to 63. UW ranged from 18 to 28, friction (F) = ranged from 12 to 19.5 balance weight (BW) ranged from 34 to 45.5,=20 What would make the BW so inconsistent? FWs are from at Stanwood's Front Weight Ceilings to about 4g over, = KR is .55 for naturals and .53 for sharps, average WW is 16.5, SW ranged = from heavy-medium in the treble to just into the light zone in the bass, = action ratio (R) ranged from 6.7 to 7.5 and averaged 7.1. Clearly, the leverage of this action is horrible - too high. We = experimented with a 17mm and 16.5mm knuckle-to-centerpin distance = knuckles/shanks. They seemed to function very well - you could regulate = the notes quite well (we tried the 17mm on one note and the 16.5 on four = notes). However, the improved leverage dropped all the DWs to around 41 = and all the UW to about 16 or 18g.=20 Looking for a bit of input here - this is too light, yes? Too = light DW and the low UW will produce poor repetition, yes?=20 Friction on the high friction notes dropped to 12 or so and BW = dropped to 28 to 30. Calculated R goes from and average of 7.1 to 6.2 = with the 16.5mm knuckles - likely down to about 6.0 with the 17mm = knuckles. Using the Overs action ratio method (we did not do actual = measurements with the 16.5mm knuckles) I estimate that the knuckle = change would drop the action ratio down from the original average of 6.4 = to 5.9 BUT, these keys have a whole bunch of lead in them. We are = thinking that, at a minimum, this action needs the knuckles placed out = at 17mm from the flange center pins to improve leverage. Then, that will = allow one or two leads to be removed from each key - remove enough lead = to make the DWs in the 50 gram range and the upweights will gain a = similar amount - around 10 grams or so and end up with about 27g UW. Ultimately, I think, this piano needs a complete releading = (setting gradational FWs) new hammers, shanks, knuckles and flanges and = gradational SWs (on some nice SW curve). Don't know exactly what the piano owner will be willing to do - = apparently it is a not-so-well-to-do church. Phil has the action at this = point to evaluate it. Anyone care to comment on our thinking here? Neither one of us are = experienced with this balancing methodology enough to decide exactly = what to do on our own. And we recognize that maybe we need to do a bunch = more measuring also. But we have a start.=20 We'll be very interested in input. Thanks. Terry Farrell (I wonder if Phil managed to drive the 135 miles home in the time = I took me to write this email?) :-( ---------------------- multipart/alternative attachment An HTML attachment was scrubbed... URL: https://www.moypiano.com/ptg/pianotech.php/attachments/17/d1/b5/2b/attachment.htm ---------------------- multipart/alternative attachment--
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