Commonly, MRZP represents the intersection point of the two rotary axes, although sometimes the two rotaries may be offset by a specific distance. This distance must coincide or be relative to the part datum PZP (Program Zero Point) of the CAM system.

To accurately set up, operate, and program these machines, it is necessary to find the intersection of the rotary centers of the machine axes. Some, but not all, manufacturers have the values stamped on their rotary devices. However, those numbers are not to be trusted, and must be recalibrated regularly.

Finding the precise center of rotation is the foundation of accurate work.

Even small discrepancies will magnify errors, further away from this machine rotary zero point.

Here are the steps to be taken:

1. Level the table by zeroing the indicator on either side of the table, as shown in Figures 2-10 and 2-11

   
   Figures 2-10 and 2-11: Method of checking the level by dial-indicating both sides of the workholding table

   
   Figure 2-12: Setting the dial indicator to zero before checking the level of the table.

2. Find the XY zero, using the dial indicator. Zero XY and A at this point, as shown in Figure 2-13 .

   
   Figure 2-13: Zeroing XY and A positions on the work-holding table.

3. Rotate A+90 degrees and touch the OD of the table as shown in Figure 2-14 .

   
   Figure 2-14: After rotating the A axis through 90 degrees, touch the outside diameter of...