Hi David, Thanks for the informative post, I remember a good deal of two lectures I've had the pleasure of hearing from you on the subject, but I'm a bit sketchy on what you had to say about how lacquer affects hammer resiliency. I remember you showing those photos of individual felt fibers magnified gawd knows how many times...but I dont remember if any of these were of lacquered felt. You did mention something about lacquer binding to felt fibers essentially destroying any resiliency each individual fiber has. Then too was the small <<hooks>> on each fiber that end up locking together as part of the felting process, but I dont remember what you had to say about how lacquer affects these. If you get time to expound a bit in the same fashion as you did below, I'd be very grateful. Cheers RicB The art and science of felt and hammer making a complex subject for sure. Whether your using cold pressed, hard pressed, lacquered or not, the best description of what we all seek is best described by the father of the modern production made hammer, Alfred Dolge who wrote in 1911 in his book Pianos and Their Makers: "The art in hammer making has ever been to obtain a solid, firm foundation, graduating in softness and elasticity toward the top surface, which latter has to be silky and elastic in order to produce a mild, soft tone for pianissimo playing, but with sufficient resistance back of it to permit the hard blow of fortissimo playing." I'd like to make a comment on Ric's mentioning that Yamaha uses Wurzen and Ray's comment that the Wurzen tends to keep more tension... The Yamaha is a hot pressed hammer and Ronson cold (or warm) pressed. Hot pressed hammers loose tension as a result of the heat. One might imagine heating up a spring that is stretched to a nice red glow. The annealing effect of the heat causes the tension to "melt" and when the spring cools off it doesn't take up its tension again. The same is true for hammer felt... so there is a distinction between tension and resiliency. Wool fibres are more resilient than any other natural or manmade fibre unless degraded by harsh heat or chemical processing. So in a hard pressed hammer it is a question of restoring resiliency and allowing room for the heat densified fibres to move. The test of tension is to take a razor blade and cut down through the crown of the hammer and watch the immediate effect of the cut opening or making a cut through the middle of the hammer molding and seeing how the hammer opens. With a hot pressed hammer the opening force from felt tension is always diminished compared to a cold pressed hammer. With a cold pressed hammer the tension then becomes a function of the complex structure of the felt and this is very difficult to quantify. I did have an interesting experience years ago. I had used a couple of sets of cold pressed hammers which had extraordinary tension and a most beautiful quality. I order more sets and found the tension greatly diminished. Nothing the hammer maker did could create the tension of the first sets I had ordered. I sent samples of the fibre to Texas A & M for analysis and the only difference found was that the average micron diameter of the sets with good tension was 21 microns. The sets with the poor tension had an average micron diameter of 23 microns. So in this case fibre diameter seemed to have some bearing on the ability of the felt to hold tension at the crown. I have seen fibres diameters of as low as 18 microns in turn of the century hammer felts... but it's a complex issue... gotta run... David Stanwood
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