David, Check the explanation for growing lead at the following: <a href="http://www.navsea.navy.mil/nswc/carderock/pub/cnsm/lead/lead_02.aspx">http://www.navsea.navy.mil/nswc/carderock/pub/cnsm/lead/lead_02.aspx</a> I suspect that your Bosendorfer was kept tightly closed. The out-gassing of the wood created an environment that fostered the deterioration of the lead. As for Wim's observations, perhaps the process is fostered by the presence of high humidity. AS an aside -- I appreciated your classes on hammers and voicing. Jim McCormac, RPT San Diego <div class="gmail_quote"> <blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"> ---------- Forwarded message ---------- From: "David Love" <<a href="mailto:davidlovepianos@comcast.net">davidlovepianos@comcast.net</a>> To: <<a href="mailto:pianotech@googlegroups.com">pianotech@googlegroups.com</a>> Cc: <a href="mailto:pianotech@ptg.org">pianotech@ptg.org</a> Date: Tue, 12 Mar 2013 13:27:30 -0700 Subject: [pianotech] Expanding leads While I have run into expanding lead problems periodically generally they seem to have been reserved for "lesser" pianos. Today I found a 1950's Boesendorfer 200 with leads expanding both in the back action and the keys to the extent that they were binding on their neighbors and on the verge of splitting things. Of course I will have to remove and replace, a large task considering the new weigh-off at the key end that will be required. My question is what is it that causes that reaction and why after such a time does it happen. This is some 60 years later. David Love <a href="http://www.davidlovepianos.com" target="_blank">www.davidlovepianos.com</a> _______________________________________________ pianotech mailing list <a href="mailto:pianotech@ptg.org">pianotech@ptg.org</a> <a href="https://www.moypiano.com/resources/#archives" target="_blank">https://www.moypiano.com/resources/#archives</a> </blockquote></div>