Especially a Mason plate! ( I'm sorry to admit---but the piano was irreparably flood damaged )And not just due to added thickness. It was much tougher stuff!!! --- "Paul Chick (EarthLink)" <tune4@earthlink.net> wrote: > Alan > My dad ran a machine shop that catered to repairs > for industrial equipment which included several > foundries. I worked for him for about 11 years. > "Jerry" was the foreman for one of these foundries. > We watched him unloading used cast to be recycled > for new cast. He'd set the piano plates aside > because they were "pig," first pour iron He'd add > some nickel to cast to give it a "little flex." > Brom's Foundry would add chromium to the mix to add > hardness and pour "nyhard" (sp) castings for > government contracts. It was very hard, and hard on > equipment. Brittle cast was for low stress, low > cost castings. I'm sorry I can't relate any > specific formulas. Some cast machined very well, > while other parts were a head ache. They had hard > spots and cavities. Until epoxies came along, we > had to bore out and press a steel sleeve in the > bearing journal to make some repairs. We regularly > junk old pianos and are amazed how difficult it is > to break up the plates. > > Paul Chick > ----- Original Message ----- > From: Alan R. Barnard > To: pianotech@ptg.org > Sent: Tuesday, August 27, 2002 6:57 PM > Subject: Re: Foundry Castings > > > Cast iron IS brittle but it will not deform nor > compress under stress and tension the way steel, > aluminum, and other metals do. Nor does it expand > and contract with changing temperatures as much as > other metals. The key point is that it holds its > shape and, most important, the critical string > length dimensions. > > I understand that cast aluminum was tried back in > the 40's or so. It would sure be nice to find a > different, lighter, less brittle material--then you > wouldn't need such a heavy wood frame either. Every > time I move a piano, my thoughts stray in this > direction ... > > I'm guessing that a lot of the metal in the > casting is just to make the plate "beefier" so it > doesn't break so easily. > > Alan R. Barnard > Salem, MO > ----- Original Message ----- > From: Delwin D Fandrich > To: pianotech@ptg.org > Sent: Tuesday, August 27, 2002 1:16 PM > Subject: Re: Foundry Castings > > > And If I haven't created enough confusion yet, > I'll toss out another one: > > Just why do we think gray iron is the best of > all possible materials to use for piano plates > anyway? What is it about gray iron that is so > special? > > We say it is extremely rigid -- but it is not. > It's brittle. Is this an advantage? > > We say it has excellent internal damping > characteristics -- but is this an advantage? Why? > > Right off hand I can think of only two > characteristics that make it a particularly good > choice for piano plates: [1] It is easy to machine > and [2] it is cheap. Neither of these has anything > to do with its performance in the piano. > > Del > > > > __________________________________________________ Do You Yahoo!? Yahoo! Finance - Get real-time stock quotes http://finance.yahoo.com
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