This is a multi-part message in MIME format. ---------------------- multipart/alternative attachment Dale: My conversations and classes that I attended with David Hughes (if I = remember correctly) led me to believe that he prestressed the board = under the central plate strut by 3 mm and then set the bearing dime, = nickel, quarter, in low tenor, mid-range, treble, respectively. That = seemed to pretty much be his method without additional measurement. I'm = sure he arrived at this method by much experience, but he didn't seem to = sweat it beyond that. David Love Dale: ----- Original Message -----=20 From: Erwinspiano@AOL.COM=20 To: pianotech@ptg.org=20 Sent: January 19, 2002 5:46 PM Subject: Re: Baldwin accu-hitch pins Subj:Re: Baldwin accu-hitch pins=20 Date:1/19/2002 3:28:10 PM Pacific Standard Time From:davidlovepianos@earthlink.net Reply-to:pianotech@ptg.org To:pianotech@ptg.org Sent from the Internet=20 Dale: I believe the Baldwin instructions call for setting the bearing at = zero degrees to begin with. After pulling the piano to pitch you then = start at the bottom of the tenor (no bass strings yet). Tap down note = 21 - 35 to 1/2 degree, 36 - 53 to 1 degree and 54 - 88 to 1 1/2 = degrees--in that order.=20 >>>>>>>> Thanks David now this is starting to make some logical sense, = to me at least. Wow 1/2 half degree isn't much for starters on a board = with real crown values. An easy way to calculate 1&1/2 degrees of = bearing is to measure the rear string length from the front bridge pin = to the aliqot i.e. measure any tenor back scale length say of 6 inches. = Multiply by.026 =3D .156". So 1/2 degree would only be .50. It would be = easy to deflect the whole central portion of the board by that much by = just leaning on it with hand pressure. By the way 1 degree is calculated = by .017 times the length. Thus, the 1 1/2 degrees that you set the upper teble range to is on a = semi-compressed=20 board, at least to the degree that setting the bearing on the = previous sections will compress it.=20 >>>>> True So notes 54 -88 are actually set at greater than 1 1/2 degrees if = you were=20 measuring from the point before the board had any downward pressure = it. >>>>Yes but the net result would be less than that because of board = compression. This would be barely enough pressure to"take the slack out = of the board " as John Hartman says ,let alone utilize all the crown = that was so carefully built into it. What I want is to press the board = fimly so that it is spring loaded enough to push back against the = string. When this happens the board are in firm resistance to each other = and this is when I believe that optimum power/sustain are approached, = especially in new fully crowned boards. With respect to my method of = setting bearing ,at the point the Baldwin boards bearing is set is the = point at which I would probably start adding 1 1/2 degrees of bearing = but not exeeding 1/4" on the longest string lengths. Moreover, if you were to go string by string, the measurable = bearing after you got=20 to the top would be something less than your initial target. The = question seems to be, when the board is already set with some bearing, = but perhaps the wrong bearing, how do you approach the problem? >> I agree. A bit of a sticky wicket =20 Can you simply go through and correct the bearing to read 1/2, 1, 1 = 1/2 degrees=20 respectively? I often wonder whether we fret over this a bit too = much .=20 >>>>>>I respectfully have to say I don't think so. If you have = the chance to change one of these and improve it in the process you'd = answer your own question. I've heard good sounding boards with a variety of downbearing = measurements. =20 Though I have not heard one of David Hughes' boards, the impression = I get from him is that we sweat over this a bit more than is necessary. = The factors that go into a good sounding board are obviously greater = than just the bearing measurements. Teasing out the variables is = difficult, to say the least. >>>>Yes but is bearing where you'd have me sweat less on if it was = your board project? There are several obvious primary factors that we = all consider essential. Good construction,materials ,crown ,adequate = bearing,reg. and of course voicing. Davie Hughes and have talked bearing at length and our methods = are very similar if not identical. His boards sound very fine. Wonderful = sustain and color. I have to say he may have been understating it a = bit. Bearing/plate set up setting in my shop takes a good long time as = I consider it a VERY primary and critical component of making the whole = system work well. I've looked at a lot of torn a part pianos over the = years and 90% of those that I liked the best had significant even = measurable bearing and crown. The other 10% are anomallies. I.e Board = stiffness due to mass not crown or bearing I"ve also had the advantage of a few less than stellar results = (which is aggravating) that I could lay at the feet of uneven or = inadequate bearing/panel compression that when remedied the tonal = results were greatly improved. To me a new board with inadequate bearing is like a fine new car wth = only a gallon of gas in the tank. It won't take you very far. Thanks again for enlightening me to the Baldwin method. I now have a = better grasp of there concept though I consider it misguided. =20 Best---Dale Erwin David Love ----- Original Message -----=20 From: Erwinspiano@AOL.COM=20 To: pianotech@ptg.org=20 Sent: January 19, 2002 2:07 PM Subject: Re: Baldwin accu-hitch pins In a message dated 1/19/2002 11:23:14 AM Pacific Standard Time, = RNossaman@KSCABLE.com writes: Subj:Re: Baldwin accu-hitch pins=20 Date:1/19/2002 11:23:14 AM Pacific Standard Time From:RNossaman@KSCABLE.com Reply-to:pianotech@ptg.org To:pianotech@ptg.org Sent from the Internet=20 > > Ron (somebody) tell me what I'm missing on the acujust in a = way I can absorb > it. What's that you say? not possible. hmmmmmmm > =20 > Dale Erwin Dale, I'm not sure what the question is here. Like you have adjusted = plate height to fine tune bearing, you can do the same thing section by section, = or note by note with the hitch pin adjustment. Your initial plate height is = determined just like you would normally do it, only your back scale target = isn't the top of an aliquot, but a vertical position on the hitch. Hi Ron Ok I get this sort of but the place where I'm hung up is that as = you start driving the strings down on the hitch your bearing increases = as does the amount the board is compressing as you go. Just like in = pitch raising. So how do you know when enough is enough and when do you = know that there is enough ,of the desired deflections so often = discussed. Meaning a 1 to 11/2 degree angle of deflection depending = where in the scale we are talking about. Dale If you shoot for somewher around 4mm up the hitch as a target, you have some room for = final vertical positioning as you find necessary.=20 Ron Once again how could a person possibly know what the final = position is? Does that make sense? =20 Ron Uhhh not yet Ron. I must be coming at this from a really = strange angle of comprehension. I took Stacy Yokums class in Reno and he = couldn't answer my question either. I wasn't the only one asking it = either. Let me try another way by explaining where I'm coming from. Ok Take a new board and new set of too tall bridge caps. Install = plate and cut the tops so that without any load on the board you have a = 1 degree angle of deflection in the lower tenor rising to 1& 1/2 degrees = thru the tenor right up to note 88. Now install all the strings from = the tenor /bass break to 1st capo section at. Tune these up to pitch. = Before you string further take a bearing string and check the remaining = deflection. Meaning once again that the soundboard is sinking under down = bearing pressure as we go. If done this way I can guarantee an = insuffiecnt amount of bearing to drive the treble in your shiny new = board. The bearing string will probably touch bridge and aliqot at the = same time or almost but that isn't enough bearing for trebles. In fact I you can't even read much deflection with the string = at all. Unfortunately this is the very method Nick Gravagne outlined in = the journal many years ago and it doesn't work unless you pre- stress = the board some. He didn't correct or I should say amend it and I only = found out he was using pre stressing and the 1 1/2 degree angle of = deflection in one of my conversations with him a year or so ago. MY point oh yes is how in the acujust system does one = approximate total and adequate deflection with any confidence that your = not creating the problem I described above.=20 My answer so far is that you can't. Its more of a guesstimate = than I'm willing to make until somebody can give me some clarification. Does this help to see my angle of deflection!!!!!!! =20 Dale Erwin ---------------------- multipart/alternative attachment An HTML attachment was scrubbed... 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