"James Holbrook" wrote in message
news:XrYLd.7157$HZ.2520@okepread07...
Hello,
I'm getting ready to turn some small parts out of aluminum.
The parts I'm making are basically discs of about 24mm diameter and 3mm
thickness with a few holes drilled for lightening. The most important
criteria are beauty (looks good with no gauling) and machinability.

I've seen all sorts of grades and am confused as to which is the better
grade to use.
What grade aluminum should I get and what type of tool. HSS or Carbide?

Any other tips I could use?

Thanks

James

You didn't mention if you're interested in starting with round stock or
sheet material-----and they can be made from either one easily. It might be
more helpful in getting an opinion in keeping with your project. Shooting
from the hip, though, I offer this:

For beauty in machining, there's nothing quite like 7075-T6. It cuts with a
bright, smooth finish, assuming you have sharp tools and apply them
properly. Next choice would be 2024-T351 or T4, but it doesn't cut with
the nice, bright shiny surface you get from 7075. My last choice would
be 6061-T6, but it would be a better choice than 2024 if you expect a shiny
surface. 2024 tends to cut with a somewhat dull surface, somewhat
resembling cast iron, but without the graphite. In all cases, use kerosene
or some WD-40 to lubricate your cuts. You can apply it with an acid brush,
or a small paint brush.

If you're adept at hand grinding turning tools, there's absolutely nothing
wrong with using HSS with some serious positive rake. If not, and you're
uncomfortable sharpening toolbits, I'd suggest a positive rake carbide with
a chip breaker. Choose a corner radius that is in keeping with the surface
finish you desire and doesn't cause chatter, say 1/32". You don't need
carbide for aluminum and I'd encourage you to learn to grind toolbits if you
don't already. Nothing will set you free when running a lathe more than
that will.

Harold