Determining Coordinate Axes

Determining the direction of machine axes is done using the right-hand rule. If you hold your index finger, thumb, and middle finger perpendicular to one another:

• The middle finger points in the direction of the Z+ axis,
• The index finger indicates the Y+ axis, and
• The thumb shows the direction of the X+ axis.

The negative directions of the X, Y, and Z axes are opposite to those indicated.
Additionally, the Z axis is always aligned with the rotary axis direction, and the positive Z direction goes from the workpiece toward the tool.

To determine the directions of the A, B, and C rotary axes, hold your right hand so that your thumb points in the positive direction of the X, Y, or Z axis.
Then the curling direction of your other four fingers (in a closed position) indicates the positive rotation direction for A, B, or C axes respectively. The negative directions are the opposite of these indicated directions.