A week or so ago I picked up a Republic-Lagun surface grinder, and (long story short) found the base to it today. (Auction, they were in separate lots for some reason.)
The grinder itself bolts to the base at four corner points. Three of them use spherical washers to compensate for any misalignment, and the fourth has this interesting jackscrew doodad:
Clearly this is a system to keep the base of the grinder (and thus the cross-slide ways) from warping as it's tightened to the base cabinet. The three washered points self-level, and the fourth is adjustable- simple in concept, but as yet unclear in execution.
One presumes that you'd snug the three washered points, then turn the jackscrew up 'til it contacts the grinder base. But how does one determine how it's loaded compared to the other three? Not enough pressure? Too much? Torque values?
Any insight welcomed.