Spiral bevel gears are typically made from hardened steel. One’s teeth of these gears are usually ground for a more precise finish allowing for little sound at high speeds. You can specify left hands or right hand based on the direction you have to run the gears
If you have a high speed application that requires a lot of torque then spiral bevel 
gears are a great choice. The gears run at 90° to each other and have “spiral” shaped tooth which gives maximum tooth surface get in touch with while rotating. With contact spread over the complete tooth the spiral bevel gear could be run much faster than the straight tooth bevel gear and handle harder begins and stops.
We make spiral bevel gears only for industrial applications.
Worm gears are found in large gear reductions. Gear ratio ranges of 5:1 to 300:1 are usual. The setup is designed to ensure that the worm can turn the gear, but the gear cannot convert the worm. The position of the worm is shallow and as a result the gear is held set up due to the friction between the two. The equipment is found in applications such as conveyor systems where the locking feature can act as a brake or a crisis stop.
The model cross-section shows a typical placement and use of a worm gear. Worm gears have an inherent basic safety mechanism built-in to its design since they cannot function in the invert direction.