How would you tram a universal table?
My mill is a universal one; for those not familar with the term it can mean a variety of things but in this case means that the table will swivel +/- 45 degrees so that it can helically mill gears and similar operations. This of course means the X and Y axis are moved out of a 90 degree relationship.
When I replace the head after using it in a horizontal mode I tram the head so that it is "vertical" with respect to the table surface (after 40 years of apprentice training I should really run a stone across the dings in the table or even have it ground before making that claim...).
However, when I swing the table around I usually only align it to the angular scale marks which strikes me as not being nessarily the most accurate. Does anyone tram their tables or has heard of a method that can be used? I did think of using a square plate keyed to the table (so aligned to the table long axis*) and using the shorter axis, measure across it. When the table is square the measured dimension should be the true dimension of the plate. This relies on the cosine though and as you approach 0 degrees differentiation becomes harder. Another thought is an accurate 90 degree block. If I align it with a DI so the short axis shows no indicator movement when traversed, if the table is at 90 degrees traversing the long axis should show no movement either. This of course relies on an accurate reference square.
Any other suggestions? I'd really prefer something that is quick and could be done without having to break down a set up as swinging the table is sometimes easier than putting vices at angles etc.
Michael
*Having been pulled up many times for mislabeling my axis, I'm hesitant to name them. I know the Z axis is the axis of rotation but...