Wim, Tim Coates and Tim Geinert here in the sunny Dakotas. We are spending a day together talking pianos and what not (mostly what not). We are here to cheer you on! TimG has had experience at University of Minnesota at Morris with the very problem you describe. The culprit was the groove for the butterfly spring in the balancier lever. The groove was worn so deep that the spring couldn't slide the proper length and locked the balancier up. TimG took a sharp tool and smoothed out the groove. These pianos were new in the 1970's and hadn't been touched since. They are under heavy use. The problem is solved. Another culprit on other Steinway pianos is the backcheck. They have been installed incorrectly (imagine that). There is a line that must be adhered to concerning the hammer shank and the backcheck. The backcheck should be divided into three sections. The shank at rest should dissect the backcheck at the line that separates the top third from the middle third. If the backcheck is too low, a pair of snap ring pliers are used to raise the backchecks. Several pianos have had the problem which created checking and repetition problems. It sure beats changing the backchecks. Goooooh Wim! Tim Coates and Tim Geinert On Dec 19, 2006, at 3:31 AM, David Skolnik wrote: > Ric - > I don't think wobble is the issue. I think that any well designed > checking system would compensate for a degree of lateral oscillation. > The lateral hammer movement you sometimes see upon release of key is > mostly due to an tail not parallel to its backcheck, or perhaps those > designs which turn the backchecks at an angle to match the unsanded > tails. In either case, the hammer pinning can be compromised. Keep > remembering that, at the volume level involved in Wim's problem (we > are still talking about Wim, don't you know) the shaking, rolling and > rocking can't be the defining issue, as the extraneous hammer motion > would still have to fall within an expected range. > > As to the issue of adjusting spring strength to pinning friction... I > had been introduced by Bill Garlick to the idea of accelerating the > jack return speed by increasing the tightness of the balancier > pinning, and the requisite increased spring strength for the same rate > of hammer rise having the secondary effect of speeding the jack at the > other end of the spring. Remember, this whole process is meaningless > on a non-butterfly spring system. As is is, Ed Foote earlier said : >> Jack speed is just not, >> imho, anywhere near the limiting factor in repetition speed >> Date: Tue, 14 Nov 2006 16:20:24 -0500 (EST) >> From: A440A at aol.com >> Subject: Re: [CAUT] Tight Jack Pinning > Seeing the proper documentation, I would entertain Ed's theory in > principle, except I would consider that the additional spring tension > could be a positive factor in helping the returning jack in overcoming > friction issues at the knuckle (mis-shapen, dirt, or rough buckskin). > The theoretical improvement of jack return would be an aid to fast > repetition however, not for checking. > > In fact, the combination of a high-friction/tension jack return > system, combined with a lightly pinned hammer could contribute to the > "fly-away" sensation Susan spoke of. In that case, tighter pinning of > the hammershank would be necessary. The problem with a high tension > rep-spring system is not necessarily the unpleasant 'kick' of the > hammer rise, but rather the increase in resistance (friction) at the > 'moment' of let-off. As I tried to describe earlier in this thread > (or its ancestor), an imbalance between the force required to depress > the key to the point of let off and that required to move it through > let off will significantly define the characteristic of that action in > pianissimo playing. > > But all this is peripheral. The main problem is that Wim has chosen > to solve the problem by redefining it. To wit: > >> Bobbling hammers means there is something wrong. From what I am able >> to figure out, there is nothing wrong with a hammer not checking. > and > >> Nothing I have tried seems to work. So for now, I give up. But if >> anyone has another answer, I will be glad to try again. > It would be tragic to allow a thread which has generated so much > attention to fade away with a WIMper. Cheer him on or threaten him, > but don't let him give up!! > > That's what he needs! Cheerleaders. > > > <cheer.jpg> > Goooooooooh WIM!! > > > Happy Holidays > > David Skolnik > > > > > > > > > > > > > > At 02:37 AM 12/19/2006, you wrote: >> Hi David and Susan >> >> This is where I always end up thinking about this issue. I envision >> that a hammer bouncing off at the high speeds we are talking about >> (even with soft play things are pretty fast) needs to not have any >> sideplay or wobble at the moment it contacts the check. The check >> will try and hold not only a tail coming down into it, but one that >> is shaking, rattling, rocking and rolling :) To.. it will generally >> have some sideways checking to attempt to hold. You can see this >> often on angled bored hammers that sometimes check and sometimes dont >> by watching closely for sideways movement when you release the >> check. Perhaps when this happens some shear force gets into the >> picture between the <<<joint>> between the check and the tail and >> once broken and the tail gets moving sideways... it also releases in >> the vertical direction. I dunno when it comes down to it... >> speculation. But firmer pinning always results in better checking >> IME. >> >> Dont know if I 100% agree about the stronger spring comment Susan >> forwarded tho. You do have to at least watch out for the feel of the >> spring in the key upon release from check. Gets really annoying if >> that is too strong. >> >> Cheers >> RicB >> >> >> I tell you what, David ... next time you have a good quality piano >> which is offending in the checking department, pin a few of the >> worst >> hammers to three swings and observe what happens. Then maybe you >> can >> explain it to me. I just know that if I do it, I like the results. >> Oh, and while you're at it, you might check the wippen flange and >> the >> balancier pinning as well, and fix them if they're very loose. But >> I've found that the hammer flange is the main problem, giving more >> immediate results than the other two. >> >> Best, >> Susan >
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