Exactly so... so once I got the rotary table centred under the spindle i'd lock the gibs on the main table. Then I clamp the workpiece to the rotary table roughly centred, turn the table so that the dti was set up against one edge of the workpiece, then rotate table 180 and indicate offset on opposite side, then tap workpiece with mallet to correct. Repeat til centred... the repeat for other 2 sides....

wheres the catch...there has to be one!