This is a multi-part message in MIME format. ---------------------- multipart/alternative attachment Thanks, Owen, I have the magazine and am familiar with the quote. Still, = this is based on tradition and handed-down 'technology' rather than test = and examination. I've checked with various foundries and iron foundry = associations and have been unable to obtain any evidence of testing or = research that has gone into this question. Now, it may well exist but = I've not yet found it. Del ----- Original Message -----=20 From: Owen J. Greyling RPT=20 To: pianotech@ptg.org=20 Sent: August 26, 2002 10:59 AM Subject: Foundry Castings "Fine Woodworking" Techniques 5, which I purchased in 1983, has an = article written by John Lively dealing with the advantages of larger = vintage woodworking machines made of cast grey iron.=20 qoute.... "Powermatic is licensed, he said, to use the Meehanite = process, a patented technology for making a high grade, close grained = grey iron that is superior for use in machinery castings. The process = ensures that the molecular constitution of the cast iron is consistent = from day to day and from year to year, a condition that makes milling = and grinding more efficient and that contributes to product uniformity. = We can control the aging time for our castings. He explained that the = traditional method of letting cast parts sit for months uncovered in the = open air is still the best means of relieving internal stresses created = by the casting process. Aging gives these stresses time to resolve = themselves before the part is milled and ground" ISBN 0-918804-17-5 Del, if you are interested I can scan the article, and fax to you.=20 Perhaps this is an entirely different process then is used to make = plates for pianos, but I somehow doubt it. I recall seeing an article = years ago about a foundry, I think in Europe where piano plates were = only one of the many products that were produced from the same raw = materials. I know Powermatic has a plant in McMinnville, Tenn. Perhaps = they have an R&D department.=20 Owen > ....Foundry castings need time to "cure" for strength.... Do you have any technical reference for this? I've been trying to = track down solid information on the subject for some time--but to no avail. It's = long been assumed and talked about--at least within the piano industry--but = I'm after specific details. What 'strength' parameters change over time? Stiffness? Impact strength? Compression strength? What? Del ---------------------- multipart/alternative attachment An HTML attachment was scrubbed... URL: https://www.moypiano.com/ptg/pianotech.php/attachments/7b/6d/7e/74/attachment.htm ---------------------- multipart/alternative attachment--
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