NCCER Millwright Practice Exam

Which gear configuration is best for transmitting power at an angle?

1. Spur gears

2. Compound gears

3. Bevel gears

4. Worm gears

The correct answer is: Bevel gears

Bevel gears are the best choice for transmitting power at an angle because they are specifically designed to operate between shafts that are typically oriented at 90 degrees to each other. The unique shape of bevel gears, with their conical surfaces, allows for efficient transfer of motion and power across different axes. They can effectively handle both high and low-speed applications, making them versatile in various mechanical setups where angle transmission is required. In contrast, spur gears are best for parallel shafts and do not provide the capability to change the direction of power transmission. Compound gears, while useful for increasing mechanical advantage in parallel arrangements, do not alter the angle of transmission. Worm gears can transmit power at right angles, but they usually do so at a low efficiency and are primarily used for high torque applications with a significant reduction in speed.