Zeroing a universal mill table

[Pete O]

I struck a problem a little while ago when doing some stub milling on the Victoria U2 universal mill. When taking more than one pass with a face mill in the horizontal spindle, I was left with a step between the two cuts, I didn't measure the step but it was visibly obvious and definitely enough to catch a fingernail on. I puzzled over it at the time and then I had a bit of a lightbulb moment a few days ago, I think the table X axis is not square to the spindle. Can anyone tell me the correct procedure for setting the table square to the horizontal spindle? Haven't been able to find any info on this anywhere. I'm thinking that if I mount an indicator on the table so that it probes the face of the column, moving the table across in the X axis will sweep the indicator across the machined face of the column. I tried this today and I get a difference of .007" across the column which is about a foot or so wide. Before I go and make the adjustment based on that I thought I'd better check that I'm not missing something. Also this assumes that the face of the column is square to the spindle- is this a reasonable assumption? I guess I could check that by turning an indicator in the spindle with the tip on the column face, like tramming a vertical head.
Given that these machines are intended to be swiveled to various angles for spiral milling etc, there must be a right way to set it back to zero, let me know if I'm barking up the wrong tree.