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Diamond grinding wheels: which alloy holds the diamonds???

Diamond wheels are increasingly cheap. So cheap, I'm contemplating using them as steel disks in a wind generator. But it hurts to leave this magnificent technology unused.  The binding metal looks like silver brazing alloy to me. What is it, how can I take it off, could I re-use it...
Perhaps not now, but I could picture a huge cup shaped wheel to grind a glass blank to a pre shaped telescope mirror


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BobS (author) 7 years ago
When I get the opportunity, I'll try to melt the diamond/ metal layer off a small diamond disk, in an oxygen poor environment. Most likely, all diamonds will float on top of the melt. It might take a while before I get the chance, but I'll definitely will make an instructable/ demolishable about it when done.

Diamond wheels come in metallic and ceramic bindings. The cheap ones have metal binding in 2 varieties: one with the silver/ 'brazing'  binding, the other one with nickel electroplated, locking in the diamonds.(thanks, Seandogue!) The silver bind seems to contain quite some manganese, definitely more than brazing stuff.
The ceramic varieties seem to use a lot of SiC (carborundum) as a filler.

Thanks Steveastrouk, for the tip of using a cutting wheel with some mods as a cup disk...
BobS (author) 7 years ago
Anyway, I found an unbelievable deal on saw blades: 3 blades round 210 mm with 24, 48 and 60 Tungsten carbide teeth!! In a very nice aluminum case for, closeout, E 6!!! (Aldi). I'm going to build the generator using 2 of these blades... Non-destructive, so perhaps later, they still can be used for cutting hardwood......!
lemonie7 years ago
Mirror polishing is done a bit differently
www.telescopemaking.org/polishing.html
And I wouldn't think you would want to be rough-cutting the mirror with power tools.

L
BobS (author)  lemonie7 years ago
As said, this is a far in the future project. But machining of huge glass blanks (roughing) has been done by amateurs. Machining all the stages, up to perfect spherical polished shape as well, by home built machines.  I used to build telescopes living in the US, but in Holland one quickly looses interest: few clear nights, cold nights and way too much light pollution.
lemonie BobS7 years ago
Yes it's "lit up like a Christmas tree" there...

L
Given the season, the only reply to that is "Oh yes you do"

Roughing optically fast mirrors is definitely where you want to use power tools.

Did I show you my 1 metre mirror grinding machine ? 

Steve
Mmm, yes I remember that (now) - I was remembering something else in the way of mirrors when I said the above, I appreciate the correction.
L
jtobako7 years ago
Just buy diamond powder and apply to a tin or copper lap.
Nickel.

Using diamond grinding disks for hogging mirrors is a well known art, even among ATMs. You don't even need a cup wheel, using a holder that lets you pull in the centre a fraction works just as well apparently.

Steve
The bonding material is more of a ceramic.  I find it unlikely you can recover the material and reshape it.  Maybe it could be re-ground and re-fired, but that's a process that requires tools most of us simply don't have.

Visit;
http://www.enotes.com/how-products-encyclopedia/grinding-wheel
or try to look for the episode of How It's Made featuring grinding wheels.