"Harold & Susan Vordos" wrote in message ...
"Rashid Karimov" wrote in message
om...
snip-----

The 6xxx aluminum is nearly impossible to slot, as it is soft &
gummy etc.

Not if you specify a T6 condition. That machines quite well, but requires
adequate lubrication while machining.


Tried that one too - to no avail. My application requires milling
hundreds of
slots (going metric for a sec): 50 to 12 mm longs, 6 to 2mm wide.
Doing it
in a single pass-per-slot is the best way to go.

Working with 7xxx allows plunge cut through 1/8 of material and then
moving the mill table to cut around perimiter. 2-flute endmills work
the best I found, 4fl get clogged up. I do use cutting oil.

Of course when using 1/16" end mill you can not crank up the feed
handle,
have to do it in .002-0.004 micro-steps. However with 1/8 endmill you
can
feed as fast as you can crank it




And finally here's the answer: use 7xxx (aircraft alloys) -
these slot just fine, down to 1/16" end-mills in 1/8" plates.
Done it myself, on HF mini-mill with great results.

You'd also enjoy machining 2024 aluminum, but it, too, just like 7075 and
6061, should be in a heat treated condition. Any of the soft condition
aluminums don't machine nearly as well as the artificially aged materials
do. Seek a T351, T4, T6, or higher condition and you'll have good luck
with any of them.

Be advised that 6061 is the only material from this group that can be
welded, and if it is, it loses the aged condition. It can be restored after
a solution heat treat, than aging once again.

Harold.