Gears must have their trees always parallel to the axis. The bevel gear operator can be designed to function properly at any angle from parallel to 150 degrees.

The bevel gear operator with shafts at 90 degrees are most common. To facilitate the correct cutting, the drawing must give the angle of the face and the cutting angle for each gear, and depth of the teeth at the outer end. When trees are at right angles, the sum of edge angles will be equal to 90 degrees, and the sum of face angles and edge angles will be equal. Just as with a hand drill, bevel gear operator changes the rotation of the mandrel to a horizontal rotation and can transmit the speed increased or decreased in the rotation. They are effective for the transfer of torque. The teeth may be straight, spiral or hypoid. Right bevel gear operators teeth actually have the same problem as straight spur gear teeth, as each tooth engages, it impacts the corresponding tooth at a time. Smooth, quiet, wear and life span are all largely determined by the speed and how the teeth come into contact. As with spur gears, the solution to this problem is the curve of the teeth, so that the contact starts at one end of the machine and gradually spread across the entire tooth.

Spiral bevel gear operator  is machined for specific types of machine tools with multiple teeth (plates) in a process known as cutting. CNC cutting speed cutting surface ensuring that the ratio of the height, depth and angle of the teeth are uniform and work well together.