True 4 axis

Fred,
What I mean by "true 4 axis machining" is this:
Mount a round, 1" dia rod in the rotary axis chuck
which is mounted on the left hand side of the X axis.
(At the present time the Y axis is switched with the
rotary axis, so the Y axis stays in one position
during
cutting while the rotary axis turns. The X and Z axes
work as usual. Let's say we want to make 4 circles,
that are 1/8" diameter and raised 1/32". Since the Y
axis is not moving, the cutting proceeds around the
rod, but of course each circle ends up elongated. Now
-
if the Y axis moved to compensate for the circle
elongation, one could mill a perfect raised circle on
a rod that is turning in the rotary axis.
Hope this explains what I mean by true 4 axis
machining. Merely switching the axes will always get
an elongated cut which isn't true to the cad drawing.
Bill Reidsema