<HTML>In a message dated 7/25/2002 9:51:23 PM Pacific Daylight Time, yardbird@pop.vermontel.net writes:              Hi Bill      I meant to comment on the "work hardening" idea you stated last week.  I have an idea what you refer to but as I see it all hammers soft or hard have some work hardening done to them as they develop string marks, compacting right on and barely under the strike surface. The results are quite different depending on the hammer.  If I understand you term or concept this is what this means.    A piano hammer is an energy storage device. It absorbs energy on impact with the string. As it begins its contact with the string it deforms/Compresses the string and then re-releases its energy that was stored, for that split second, back   into the string. As the string is deformed it to releasees its stored energy imparted by the initial hammer blow pushing the hammer away. Basically two springs pushing on each other rather than a head on collision If this is somewhat clear the next part should fall into place   Work hardening and the subsequent development of some kind of molecular change in the felt beneficial to tone is only possible if the hammer has a certain amount of stiffness or limited resilience to begin with. With unlimited resilience (too soft) the hammer no longer works as a nonlinear felt spring and cannot take advantage of work stiffening/hardening. It is too linear, unable to get progressively stiffer with increasing levels of energy applied, it becomes instead more of a damper. Hardeners/stiffeners (lacquers) must be applied to limit resilience then work hardening can apply.      For the overly plasticized or (petrified felt) hammer work stiffening happens at the immediate surface only compacting surface felt seen as the string grooves which cause a nasty sound we all dislike, but does nothing else except annoy & assault piano tuners ears. Not much musical dynamics to be had here.    However for the hammer with a reasonable amounts of reselience/stiffness, meaning not too much needling or juicing to get close to desired piano tone, work hardening is something that happens not only in the string grooves but deeper underneath and thru out. The felt takes on a set but doesn't freeze up. Sometimes it shows up visually like the hammers have taken this set, squashed a bit on the top and out at the shoulders. I've seen this in Isaac,Ronsen and Stwy hammers.  Primarily though it shows itself in the tone which is what I your point was Bill. The tonal ripening.   Hmm I like that Bill       The more the felts resilience is stolen during pressing the less likely work hardening has any effect or validity to its tone production qualities.       >>>>>>>>>>Dale Erwin>>>>>>>>>>>. <BLOCKQUOTE TYPE=CITE style="BORDER-LEFT: #0000ff 2px solid; MARGIN-LEFT: 5px; MARGIN-RIGHT: 0px; PADDING-LEFT: 5px"> It is the hammer which has not had its resilience thermoplasticized out of it which, soft though it may be, is ready for working-hardening. This "after-market" process really ripens the resilience, and allows the tone to mature into something great. Bill Ballard RPT NH Chapter, P.T.G. "If you jabber like a jabberwocky and if you walk like a jabberwocky, You must be a jabberwocky"      ........... two punchy guys +++++++++++++++++++++</BLOCKQUOTE> </HTML>