On Wed, 13 May 2009 19:38:14 -0700 (PDT), wrote:


a)using it as a rotary table, you will centre it under the mill
spindle with the x-y mill controls. so it doesn't matter if its out a
bit in the chuck.

True only if you don't rotate the rotary table.

The mill's x-y controls can't take out centering error in the chuck
because the x-y position of the mill table remains constant while the
x-offset and y-offset of the piece in the chuck vary with the
rotational angle.