Yes, practice at regulating spring tension does help. But my experience is that when balancier and hammershank pinning is too loose, the spring tension regulation has to be so light that it isn't reliable. The spring has to regulated so weak that the slightest changes in humidity have a great effect on function. To regulate the spring tension so that it doesn't throw the hammer past the drop point against the string, creating the bobbling hammers at mp playing, you wind up with a spring not strong enough for the wippen to reset properly on a firm blow. More firm pinning prevents "bounce", especially in the jack, but also in the hammer. The stronger spring tension allowed by firmer pinning "lasts longer". Jeff, I've had the same experience, with a worn and loose S&S B action which seemed to pass all my tests for regulation and dependability -- but the pianist would do two fast notes like a stutter, with a straight tight finger (ba-DING!) and jam it every time. I even needed a lesson at playing two notes like this before I could reproduce the jamming to see if I could get rid of it. I chased this problem down many blind alleys, including the possibility that the jack was getting trapped between the cushion and the knuckle. This was an ex-teflon piano with some geometry problems. I had to tear some felt off the window cushions because some of the jacks were pressing into them. I got the jacks free but the note jamming problem was unchanged. In the end, I realized that the hammer tails were getting caught on the way up by the backchecks after the fast initial note and before the hard-played second one. This was partly a problem with the tail shape, which was slightly dished inward around the shank insertion point, so that the bulgy Steinway backcheck could lodge there, but also the loose hammer pinning which let the hammer bounce back and forth freely and very quickly, so that it was below the backcheck and rising as the second note brought the backcheck forward to catch it. Nothing stopped the jamming till I repinned the hammers tighter (they were 14 swings or so) and some of the wippen flanges and balanciers as well. Then the springs could get tighter without the hammers escaping check, the hammers stopping bouncing up and down so quickly, and the pianist couldn't get them to jam anymore. When shaping tails, I make extremely sure that they are a good steady arc, so that there isn't any little dish for the check to catch. (I made a jig from Bill Spurlock's design which swings them past a sanding disk, for a perfect arc, which I start at the shank insertion point.) This also keeps them from sometimes sliding right through the check on a hard blow. Some of the new Steinway hammers I've seen seem to me to have too shallow an arc, so that it is too easy to push them through the check. Almost all the time, especially at first, this seems to cause no trouble, but now and then as the piano gets heavy use, it can start to be an issue. I like a good wedging when the tail is caught, so if you tapped down on the top of the hammer, it would tighten into the check instead of pushing through. It helps repetition as well, to have really good tail and backcheck geometry. I saw those high speed photos of super-fast repetition. (Kawai, I think? Thanks, Don Mannino.) What struck me was that even with all the flexing and trembling, and the incredible speed of repetition, the hammer tail was caught after each and every note. After seeing that, I realized that if we are to get really good repetition, we need superb checking. Mike Reiter's good class on repetition(repetition) corroborated this. The other reason I like somewhat firmer hammer pinning than is now fashionable is that when the pinning is too free (even if the hammer doesn't flex side to side) I can feel the vibration in the key as the hammer trembles when rising after being released from check. If the pinning is a little firmer the spring can be strong enough without the hammer getting too excited as it rises, even if it goes up quite quickly. Decent keybushings help absorb that vibration so the player doesn't have to feel it, too. As anyone can see, I sometimes work on pianos which have had heavy use and are ready to get a little friction back, and also on pianos which have been rebuilt but still have some problems, especially after a lot more playing. In a better world, all initial geometry would be perfect, all rebuilders would be infallible, and all budgets would expand to pay for excellent, uniform, and perfectly fitting new parts as soon as actions got loose. In the real world, we need to cope as best we can. Susan Kline -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://ptg.org/pipermail/caut.php/attachments/20090815/45bb8c9a/attachment.htm>
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