Hi Del, Les, Theodore, and all the ships at sea, The major advantage I see to plate bushings, besides being a terrific drilling guide, is that they supply an excuse to make the hole in the plate big enough to clear the tuning pin. I don't claim that they have any holding power by themselves, or that they minimize flag poling even. (I really don't think flagpoling is a problem.) They KEEP THE PIN OFF OF THE PLATE. Sorry, that wasn't shouting, it was emphasis. <G> Keeping the pins clear of the plate lets the pinblock do it's job of getting a grip on the pin. A pin will hold in a block even when the hole it's in is pulled oval by string tension and humidity swings because the tension supplies enough friction around 270 degrees of pin to hold the torque. On the other hand, if the pin is riding the plate, there is no tension produced friction and the pin loosens in the block much sooner than it would have with plate clearance. The immediate noticeable effect of pins riding the plate is feel. The final problem in tuning any given string (after the string bearing points and segment tensions are under control) is leaving the pin in a condition where the bottom of the pin is "ahead" of the top, so it is torqued back by the string tension in a way that the opposing forces of tension and torque balance. The system is stable because it's balanced. When a pin rides the plate, I find it more difficult to feel exactly what the bottom of the pin is doing. Again, this is much worse in an older piano than a new one because the block's grip on the pin is tighter at the top of the pin, than at the bottom in an older piano with riding pins. The torque is so erratic from pin to pin, with some of the pins not riding the plate at all, that I have to switch "modes" back and forth so many times, and consciously fight the process that the tuning becomes much more tiring. It's also more likely that I guessed slightly wrong on final pin placement and I tend to find more slightly noisy unisons in post tuning checks. The long term effect is in the differences in pin torque. Each seasonal cycle widens this difference between "riders" and "non-riders". The riders get looser, quicker, than non riders. This is least noticeable in new pianos, but becomes a real problem as a ten or fifteen year old piano that cost as much as a room addition has a dozen pins too loose to hold string tension. That's about it. Pianos with plate bushings tune easier than those with pins riding the plate, and the pins remain tighter in the block, and of more uniform torque, for longer than those without. Open blocks would be ideal, the best of all combinations. The issue, as I see it, isn't really the bushings, it's the plate riders, or lack thereof. Steinway could get a dramatic improvement in both long term tunability and pinblock life by just drilling the plate holes bigger. Baldwin's granite pinblocks have the same troubles when pins ride plates, but they are nearly as impossible when they don't. They ought to be using a more forgiving material, like titanium, AND drilling the plate holes bigger. <G again> Boy, I sure hope somebody out there agrees with at least SOME of this stuff. Still ducking, still covering, Ron At 10:17 AM 12/30/97 -0800, you wrote: > >Ron, Les, Theodore, et al., > >I have a hard time getting too worked up over the controversy concerning plate bushings. They were originally invented to be >a drilling guide. And once the drill goes through them, they really aren't good for much. After a couple of annual weather >cycles the wood has tried so hard to expand between a rock and a hard place (the pin and the plate) that the wood fiber is >pretty well crushed. Not to mention the wear and tear from our tuning efforts. > >I spent about five years tuning almost nothing but Steinways. Without bushings. I could never understand the reported >problems folks were having tuning pianos without bushings. If the piano had level pins (in the seventies and eighties none of >them came that way, we had to do it during prep), consistent pin torque (ditto), uniform string coils (ditto), etc., tuning >stability simply wasn't a problem. I had a whole lot more trouble with Baldwin's and their granite pinblocks -- but that's >another story. Or Mason & Hamlin's with their plate bushings. > >I have long suspected that the fondness many tuners have for tuning Yamaha's, etc., was simply that Yamaha paid much more >attention to those details that actually do make tuning easier and more stable. > >The only plate bushing I've ever seen that might really be effective was the one used by Knight for a while. (I don't know if >they are still using it or not. Barrie?) It was phenolic and was hard enough to resist being crushed by the flagpoling tuning >pin during tuning. > >The system I really do like is the exposed pinblock. It is possible to use both a shorter pin and one with a smaller diameter >and still not have excessive flagpoling. It's a great system when done correctly. > >Del > Ron Nossaman
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