Jim Wilkins fired this volley in news:2fc04650-7e3b-
:

Doing that with a level sensitive to 0.0005" in 10" isn't easy.

Nope, but using fine wire placed carefully the same distance from each
end while testing is better than flat shims. A flat shim bears only on
one edge when slid under a tilted level.

My surface plate has adjustable legs, and although the adjustment thread
is coarse, I have no trouble getting it level to within a half-thou per
foot. Just gentle "taps" on the adjusting wrench results in almost
imperceptible movement of the screw, but noticably moves the plate.

Somehow, my concrete slab doesn't tend to tilt when I walk around near
the surface plate.

LLoyd