On Thu, 4 Apr 2013 19:06:19 +0000 (UTC), Cydrome Leader
wrote:

I understand how much everything on a lathe, including the work can flex, but
this just doesn't make sense to me,

If I turn down say a 1/2 aluminum rod that's chucked and extends only a half inch
and dial in 0.01" of feed and measure the before and after diameter with a
micrometer the diamter decreases by 0.02" Perfect.

The part I don't get is if I take a smaller cut of say 0.001" it will remove more
than 0.002" of diameter. For example if I need to remove 0.003" of diameter,
feeding the crosslide 0.001" will come pretty close.

It only seems to happen with very thin cuts. I'm only turning the crossslide dial
in one direction- there no backlash weirdness going on.

Why might this happen?

Perhaps your cutting tool has too much "draw" and is pulling into the
work. Try locking the gib screws on the cross-slide before making the
cut.