For reasons that are beyond my comprehension, I loosened the bolts, scraped out what I could between the column and the base, swept the table, and added some shims. Actually, I swept the table as a test before ever messing with the bolts.
First, my Chinese combo wrench was no match for the Chinese lock washers. Geeeezzzzzz. Hats off to Enco, because their bargain wrench (23 mm was the charm) held very securely, allowing me to use my bargain deadblow hammer.
The readings matched what I expected from the face mill: the head was leaning to the right (almost a shame to fix it). I was a little surprised to find about seven thou at 5 inches. At this point, I have it within a couple thou, and should get more shims before messing around any more. The alignment should be much improved, and I doubt I have the material to do better.
So far, I am using all one-thou shims. Would you like me to get some thicker ones? While I'm at it, are there any cheap but good indicator holders I should get? I cobbled together a contraption using parts from the Baker kit and at least one import mag base. Maybe that's good enough. Most of my dti work is spindle mounted for aligning my vise, and that is easy (slap it in a collet) and works well.
To tighten the bolts, I gave them a good tug and then a few light whacks with a mallet. Was that overkill? They were _really_ tight before I got to them. Do I need to do something else? Having seen a vise slip, I have renewed respect for milling forces, but obviously, stripping those bolts would be a BAD idea =:0