Most machine slides for many decades, and many even today, have been simple (but accurate) cast-iron linear bearing surfaces, such as a dovetail- or box-slide, with an Acme leadscrew drive. With just a simple nut, some backlash is inevitable. On manual (non-CNC) machine tools, a machinist's means for compensating for backlash is to approach all precise positions using the same direction of travel, that is, if they have been dialing left, and next want to move to a rightward point, they will move rightward "past" it, then dial leftward back to it; the setups, tool approaches, and toolpaths must in that case be designed within this constraint.