[UWP_Wes]

Fewer flutes can be thought of as decreasing spindle speed. This is important to the router folk, who often can't turn the spindle slowly enough with harder materials. Hence the one flute endmill was created for just such an audience.

So let me get this straight, the one flute end mill is designed for routers because they cannot run their spindles slow enough?

The reason for the single flute end mill is that they cannot get the feed rate high enough to get the chip load where it needs to be to prevent the flutes from clogging. The way you describe it is just confusing.

You need to be very careful about advising people to slow their feed rate in aluminum. Slow feed rates in aluminum lead to BUE and flute clogging. You have to maintain the chip load to prevent this.