[Spridgets] Rearden metal

Dean Hedin dlh2001 at comcast.net
Fri Dec 14 22:34:20 MST 2012

I find myself for the first time machining some 7075 Aluminum alloy on the
lathe the other evening.

This is my new favorite metal.  It is as strong and hard as many steels yet
it machines very easily.

The presence of chromium in this alloy does not go unnoticed.  The surface
finish is spectacular.  When cut with a fine tool you get that prismatic
effect, like looking at a CD. This happens with other aluminum alloys to
some extent, but they soon dull over after short time.  7075 stays bright.

I can't believe I've wasted my whole life messing around with 6061.

I'll have to get some more of this stuff.  It's expensive from the big
online vendors like McMaster or MSC, but there are a couple guys on ebay
with very reasonable prices.

In fact I've discovered ebay is the way to go for metal stock.  You can
often find oddball stuff that people have left over from big projects that
they just want to get rid of. I was able to get four foot of bearing grade
stainless steel rod like this.  The shipping cost more than the rod!  The
same stuff from McMaster would have cost over $150.

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