---------------------- multipart/alternative attachment To all Hammer Heads In the previous thread I was trying to convey the way I see that a hammer is made & if you followed that then you see that I have a definition of tensioned felt in mind. However what I failed to articulate clearly is that Tension & compression go hand in hand in the hammer pressing process. As I stated, & piano hammer makers can tell you, that too much tension can be achieved during pressing in the outer layers of felt and it can & will rip open in the crown. This is the elastic limit of the felt. As the stretching of the felt on the outer perimeter happens the inner parts of the felt are compressing. It has too because of the stretching of the outer felt, the triangular shape the felt strip is cut & the hammer press pressure itself. To prove this to yourself take any kind of tenor or bass hammer & cut thru the molding with a band saw small hand back saw up to the tip at the underfelt. Now that the molding is separated if it actually has tension the 2 halves of the molding will move away from each other as the tension is released & the middle compressed part will unload. Squeeze it back & forth & back & forth & you can visually see tension & compression phenomena happening at the same time Unless heat & pressure keep the felt from approaching its elastic limit only so much density/compression can be achieved in the middle of the hammer by strictly tension, which can be considerable but not for the kind of hammers some prefer. I believe this is one reason why we've had so many bad sets of over hard hammers in the past. Manufacturers have simply used heat or steam to densify felt & render it's natural properties less or unusable. Hence steam voicing, excess needling, voice grips. We all want hammers that work the way intended & it seems that in many places its getting wwwaaayy closer. That's the way I see it WIllis, nice to hear your out there. Regards Dale Erwin Erwins Pianos Restorations 4721 Parker Rd. Modesto, Ca 95357 209-577-8397 Rebuilt Steinway , Mason &Hamlin Sales www.Erwinspiano.com ---------------------- multipart/alternative attachment An HTML attachment was scrubbed... URL: https://www.moypiano.com/ptg/pianotech.php/attachments/50/73/b6/8b/attachment.htm ---------------------- multipart/alternative attachment--
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