RE: [CAD_CAM_EDM_DRO] Cutter head loads....anyone?...anyone?

An upper bound on the cutting force would be the spindle torque divided by the
cutter radius (with all appropriate unit conversions applied).
This upper bound is reached when the cutter is making a very shallow cut so that
all the cutter torque is turned into parallel (and thus reinforcing) cutting
force vectors (more or less parallel to the feed).

On the other hand, if you are cutting a slot using the full width of an endmill,
the torque turns into a bunch of force vectors oriented all around the
half-circle of active cutting; the net force is then smaller and oriented at
right angles to the feed direction.

Note that spindle torque is spindle power divided by spindle rotation rate
(again, with appropriate conversions applied). So slowing down the spindle at
constant power *increases* the cutting force, as does using a smaller cutter.
-Kevin Martin