Hi,

I have several metal disks I am going
to clamp together and drill holes in.

The yellow holes in the drawing are
what I want to drill.

I don't know how to find the center of 
the disks.  Once I know the center,
I can align my milling machine head
to the center, move the table on
the x axis to get the drill over
the outer diameter of the disk, drill
one hole, spin the rotary table 90
degrees, and drill another hole, etc.

How do I get the disk centered on
the rotary table?

Rich