X-axis is for left / right movement;
Y-axis is for forward / backward movement;
Z-axis is for rotating movement;
H-axis is for up / down movement;
A-axis is for "swinging" movement.
2-Axis machines include X-axis and Y-axis;
3-Axis machines include X-axis, Y-axis and Z-axis;
4-Axis machines include X-axis, Y-axis, Z-axis and H-axis;
5-Axis machines include X-axis, Y-axis, Z-axis, H-axis and A-axis.
The more axes the machine has, the more flexible it is. For example, for making brushes with horizontally flat surface, operator will need a 2-axis machine; while for making brushes with cambered surface, or for making cylindrical brushes, operator will need a 3-axis or 4-axis machine.