"Tom Gardner" wrote in message
. net...
snip---

I NEVER though I'd be asking a speed/feed/lube question but I'm curious
as to how I can do this better. Is the 6061 just softer/gummier? I have
54 more parts to make and as much as I like doing the work I hate wasting
time scraping the parts. I hate cleaning lube off of them too. Actually,
I think I'd much rather just draw the stuff and have it magically appear
on my desk.


What Ned said, and don't be afraid to moisten the cut with some kerosene.
What's happening is you're getting a slight amount of chip welding to the
cutter, which then streaks off on the part. A tiny amount of lubrication
will prevent that from happening, and improve the surface finish in ways you
won't believe. Something as simple as dragging a moistened acid brush on the
cutter will make a huge difference. You need not flood the material, and if
you have an aversion to kerosene, use some paint thinner. If you choose
paint thinner, it will even evaporate cleanly, so it's not very messy. Don't
machine aluminum dry if you want good performance. Use an air hose for
cleanup. Those of us that work(ed) in the industry do-----and none of us
are dead up to this point. Air hoses are an important part of a shop. .
Just don't blow chips towards the ways.

The nice material you spoke of is likely 7075------if not, it's likely 2024.
Both of them machine much nicer than 6061, which tends to be a little soft
by comparison, assuming they are artificially aged (T condition from T351
upwards). 7075 is high in zinc, and cuts very clean, with a shiny surface.
2024 cuts fairly cleanly, but never with a shiny surface.

Did you use the same end mill for machining steel previously? That's a
mistake. End mills that are ground for steel have less clearance, and lose
the keen edge, desirable for aluminum, fairly quickly---------resulting in a
poor finish when used on aluminum.

There are special grinds available expressly for aluminum----might be worth
the investment. They're marked aluminum on the shank.

Harold