This is a multi-part message in MIME format. ---------------------- multipart/alternative attachment Terry, Are these original parts, except for the hammers?=20 Original keybushings with well worn key pin grooves.=20 Original wippens with excessive saddle/ capstan grooves? Pinning? Verdi Gris? 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! Tom Servinsky ----- Original Message -----=20 From: Farrell=20 To: pianotech@ptg.org=20 Sent: Thursday, August 04, 2005 7:52 PM Subject: Action Balancing/Leverage Quagmire 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/99/cc/0c/ed/attachment.htm ---------------------- multipart/alternative attachment--
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