How to cut aluminum hard drive platters?

After determining that a hard drive platter is aluminum (I don't want to try to cut the glass ones), how could I cut it neatly?  I'd like to cut out neat rectangles for a small kaleidoscope.  I tried a hacksaw, but it was a messy cut, and I expect it bent the optical surface a bit.  I tried a rotary tool with cut-off discs, but the aluminum chewed up the discs really fast--I could see the discs shrinking before my eyes into tiny circles.  

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nurdee15 years ago
Depending how much you are cutting, and how much you are willing to spend you could use a laser cutter.

There are online places where you can send what you want cut and for a price they will cut it for you.
arpruss (author)  nurdee15 years ago
Can one cut highly reflective surfaces with a laser?
nurdee1 arpruss5 years ago
I don't know, that is an interesting question. I never thought about it.
If you clamp the sheet close to the cut with soft jaws, a hacksaw should be fine. For thin sheet, it is better to cut at an angle close to the surface of the sheet instead of only on the thin edge.
arpruss (author)  The Skinnerz5 years ago
I was just finding it was producing a really rough edge with the hacksaw. I was using a 32tpi blade. Should I use a finer one? Or switch to a carbide grit blade? (I've heard aluminum gums things up, though, so that might not work.)
The finish shouldn't be too bad, even with decent 25 TPI blade. If it needs improving, virtually any file should acceptably clean up thin aluminium. Alternatively, you could have just ended up with an unusual alloy, making it difficult to work with.
A neat trick for cutting thin material without too much damage is to put the saw blade in backwards and still cut on the forward stroke. It takes longer but makes a finer cut.
Burf5 years ago
Because you are trying to make a kaleidoscope, I presume you want to keep the reflective surface as intact as possible.
I can't say I have done this but based on your experience and things I have done in the past, I would score the reflective surface, where I want the cuts, with a carbide tipped stylus and then use a heavy duty cut-off disk (the fiber mesh reinforced kind) in the Dremel to make the actual cuts.
Cutting thin sheet metal with a toothed saw will almost always produce a ragged edge. Tin snips might work but would likely play havoc with the reflective material on the disk due to the tendency of the snips to bend the metal.
Vyger5 years ago
A small band saw or jig saw saw with a metal cutting blade would work. Just watch out for the metal fragments (saw dust)