wrote in message
ups.com...
The indicator base was placed on the column in order to eliminate any
possible movement of the wheelhead. The measurement does therefore
confirm the flatness of the table which translates into the
straightness of the ways.

No, it does not. No more than running an indicator along a mill table
confirms the squareness of the mill head. Look at it this way. If your
wheel is fixed (which it is) and the table rises and falls, the surface is
ground in a corresponding pattern, therefore yielding what appears to be a
surface that is flat. When you run an indicator on the table, all it's
telling you is how faithfully the wheel has followed the pattern, the ways.
It may or may not be flat, and most likely is not, especially if you're
using an older machine. . You can't check flatness that way--it should be
done by comparing on a surface plate of known flatness. Only then can you
discern the rise and fall of the surface, which then translates into
flatness.

Harold