"Jon Elson" wrote in message
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Harold and Susan Vordos wrote:

"Grant Erwin" wrote in message
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snip-----

You will when you're faced with a serious application. Don't think so?
Try using a 4 flute half inch end mill taking a serious cut (full width
and
half inch depth) on some ½" 6061-T6 aluminum plate, high spindle speed
(4,000 RPM) and fast feed. Then lets talk.


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.
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?

Jon


No, HSS, which can deal with a cut of that nature with no problems as long
as you don't subscribe to the theory that how an end mill is ground makes no
difference as to performance. The amount of relief for four flute end
mills is such that they don't respond well to rapid feeds, so when you crowd
them, they tend to drag on the bottom of the primary relief, plus the chips
tend to overwhelm the flutes.

Have you ever operated a hydraulic duplicating (tracer) mill profiling
aluminum? You can generally plunge diameter depth and run like hell so
long as you lubricate well and use 2 flute end mills. Makes all the
difference in the world.

Harold