"Jon Elson" wrote in message
...
Well, I NEVER run an end mill with a plunge depth equal to the diameter.
My general rule is that the plunge depth should never be more than 1/2 the
tool diameter, ESPECIALLY when cutting at full width. Maybe some
end mills can take this, but to my mind, that is really pushing things.

You should try taking heavier cuts. Roughing endmills can easily meet this
ratio in tool steel, and exceed it in aluminum.

Just buy two of the same endmill - run the first progressively harder until
it breaks (_if_ it breaks, perhaps), and then back off the feeds for the
second one - only half kidding.

It has been my limited experience that feeds and speeds in aluminium are
usually dicated by the spindle horse power.

Of course, on a finish pass, I might use the full length of cut of the
cutter,
but the width of cut is real light.

Are you talking about solid carbide cutters, here?

HSS. Coolant (lots) is important at this surface speed (300-500 FPM) to
prevent chips from welding to the cutter.

As an aside, it's interesting to see the feeds and speeds for aluminum that
the guys over in AMC are using. 5,000 FPM with diamond cutters.

Regards,

Robin