Spiral bevel gears are usually made from hardened steel. The teeth of these gears are usually ground for a more precise finish allowing for little noise at high speeds. You can specify left hands or right hand depending on the direction you should run the gears
If you have a higher speed application that requires a lot of torque after that spiral bevel gears are a great option. The gears run at 90° to each other and have "spiral" shaped teeth which gives 
maximum tooth surface contact while rotating. With get in touch with spread over the complete tooth the spiral bevel gear can be run much faster than the straight tooth bevel gear and handle spiral gear china harder starts and stops.
We make spiral bevel gears only for industrial applications.
Worm gears are used in large equipment reductions. Gear ratio ranges of 5:1 to 300:1 are normal. The setup is designed so that the worm can turn the gear, but the gear cannot change the worm. The position of the worm is usually shallow and as a result the apparatus is held set up because of the friction between your two. The equipment is found in applications such as for example conveyor systems in which the locking feature can become a brake or an emergency stop.
The model cross-section shows a typical placement and use of a worm gear. Worm gears have got an inherent basic safety mechanism built-in to its style given that they cannot function in the invert direction.