.... Because it "creeps".

I have only one axis (x) wired right now. When the drive is powered on,
but with no input signal, the table imperceptibly slowly creeps. I
only noticed it because some tools fell off the table as it moved by
perhaps 8 inches in an hour.

There is a "test/offset" pot on the board that, if turned properly,
shifts input signal and makes the table move. I could easily set it so
that the mill does not _visibly_ move. I have not, however, been able
to get rid of the slow creep.

I may call AMC on Monday to find out.

i