What type of gears are cut at a slant?

Helical gears are characterized by their teeth being cut at an angle or slant relative to the axis of the gear. This slant allows for smoother engagement of the gear teeth, resulting in quieter operation and a more gradual transfer of power compared to straight-cut spur gears. The alignment and gradual contact help mitigate shock loads during operation, which can be particularly beneficial in applications requiring high speeds or higher torque levels.

The design of helical gears also permits them to carry more load compared to spur gears of the same size due to the increased contact area between the gear teeth. This makes helical gears a popular choice in various applications, including automotive, aerospace, and industrial machinery.

In contrast, spur gears have teeth that are straight and parallel to the axis, while bevel gears are typically used to change the axis of rotation and have teeth that are cut on a conical surface. Worm gears, on the other hand, comprise a worm (which resembles a screw) and a worm gear, and are primarily used for transmitting power between non-parallel shafts at various angles.