An indicator under the spindle will only show you how your grinder will grind beneath the spindle. Ordinarily, we see more table way wear at the ends of the table travel. This does not necessarily show on the indicator. If there is drop off that is constant toward the ends, the indicator below the spindle will show that the table and chuck are perfectly flat left to right, but that is not necessarily so. Put a known good precision straightedge across the freshly ground chuck and see what you get. If the freshly ground chuck and/or freshly ground table match the straightedge, then the ways are probably also properly flat, depending on the grind job quality. If the surfaces are convex, then there is more wear (or lower areas) at the ends of the ways. If the surfaces are concave, then there is more wear (or lower area) in the center of the ways. It works much the same in the cross feed direction as well. Perfect barrel or trough shaped ways under the spindle will show no indicator movement. In reality, the best way to check the ways is to check the ways themselves, see Connelly. The table usually comes off quite easily.
