Tramming X & Y

[tooManyHobbies]

Is there anything more frustrating than the tramming process? (At least for the first time!)

I got it close but I'd like to do better. I'm off a couple thou in X and almost twice that in Y. While doing it, two questions came up:
1. Is it important that the z-axis column is parallel to the tables' x axis? Theoretically I think it doesn't matter, but practically it does, especially while trying to tram it!
2. I used shims to tram the Y axis, but I wonder if it could be done quicker and easier if I drilled and tapped a large screw hole near the top of the round part of the column rotating parts. It could only be used to tilt the column backwards, but so far that's the only direction mine has needed. Which is better: shims or a screw?

tom

[photomankc]

If Z is not perpendicular to the X and Y then you get positional error when you change Z position, but that's a square column mill. If this is a round column mill then I think it doesn't matter because you cut in Z with the quill and it's all lost when you loosen the head up to move up or down anyway. You can tram X and Y with the column cocked as long the head has enough movement to compensate.