After a quick deburring of the bottom, set this up on a surface plate. The bed was flat to within 0.01 mm (0.00025") and the fixed jaw square to within the ability of my tools to measure it. The jaws needed a little adjustment to get them aligned, and the tops are then flat to within 0.015 mm. Finish is generally nice, but I would dismantle, clean and lubricate before using to get the smoothest action, like any other machine tool. Pretty impressive for the price.