Lathe Coordinate System

Most lathes are 2D machines based on a Z-X Coordinate System. As shown in Figure 8.5, the Z-axis is parallel to the machine spindle and the X-axis is perpendicular to the spindle. Normal spindle rotation is counter-clockwise, though direction can be reversed for left-handed threads just like with a mill by commanding the proper G-code.

Notice how the turret is set at an incline from horizontal. This so-called "slant bed" configuration keeps cutting chips from accumulating on flat surfaces inside the machine.

Also notice that the tool approaches from the top of the part. This is known as an upper-turret configuration, and requires the tool be placed in the holder upside-down as shown in the inset view in Figure 8.5.

Figure 8.5: Lathe Coordinate System