[mb300sd]

On my SX2.7, there's no way to adjust the tilt of the head in relation to travel in the Z axis - it's one single casting. I can only adjust the tilt of the column by shimming.

So I can either have the travel along the Z axis square the the table, but with the cutter at a slight angle, or have the spindle trammed but with a slight shift in the X/Y axis as the Z moves up and down. Which adjustment is more important to have dialed in?

[cncuser1]

You want the 3 axis mutually perpendicular, do this first.

If the axis of the spindle is not parallel to the axis of the X axis, first make sure the gib of the head is properly fitted and adjusted. Then look at possibly scraping the dovetail of the head.

How much is the spindle axis off?

[mb300sd]

I have not checked how far off it is yet - I'm currently rebuilding my spindle and waiting for some bearing spacers, so no place to mount the indicator for now. Just doing research on what I need to adjust on a new machine. May be a non-issue (hopefully).

[machinehop5]

...Bench Top machine's need to be correctly Leveled and bolted down to what ever you are using for a Bench/Stand. It is possible to twist or even break the Base when clamping the machine down. So, start with a good Flat Bench is a good Idea.

DJ

[CL_MotoTech]

Keen has a good video on squaring the base of the mill.

The table should run square as measured by a level. Achieving this requires a leveled base setup as mentioned by m5.

The column is another bag of worms all together.

[dazp1976]

On my SX2.7, there's no way to adjust the tilt of the head in relation to travel in the Z axis - it's one single casting. I can only adjust the tilt of the column by shimming.

So I can either have the travel along the Z axis square the the table, but with the cutter at a slight angle, or have the spindle trammed but with a slight shift in the X/Y axis as the Z moves up and down. Which adjustment is more important to have dialed in?

Bummer.
This is one reason why I went with the AMAT25LV from Amadeal instead when I was looking for a mill.
Shim the column to get the spindle level with Y axis and call it a day. I can't see a way to do the head alone.

See, with mine, the saddle and head can seperate. So I can put a wedge spacer between them. It's 0.16mm out whichever why I go with it.
So I skim a 5mm thick flat piece of ally along it's length that has 0.16mm difference either end. Bolt it in there, and I can get both Y&Z near perfect.
(Just in case you decide to change machine in the future.)