and miter gears are conical-shaped with teeth cut on their faces
which transmit power and motion between two shafts positioned at typically a
90-degree angle (or less for some bevel gears). Miter gears, a special kind of
bevel gears, must work in pairs with the same face width, number of teeth,
pitch, and pressure angle, and operate at a 1:1 ratio. Bevel and miter gears
come with either straight or spiral teeth. Straight bevel teeth are tapered and
are preferred for slow-speed applications, while spiral bevel teeth are curved
and oblique, and are suitable for high-speed and high-performance applications.
Gears are available in a variety of materials, including stainless steel, cast iron, brass, and plastic, depending on application. There are several other factors to consider when selecting the appropriate gear for an application. The gear’s outside diameter is the longest linear distance across a gear. The bore diameter is the distance across the hole located in the center of a gear, where the mounting shaft will be inserted. The hub diameter is the distance from one tip of the shoulder (the hub) to the other. The thickness is the distance measured from the tip of a gear tooth to the gear’s bore or base (for a gear rack). The number of the teeth refers to the number of teeth around a gear. The pitch, also called the diametral pitch, is the number of teeth divided by the pitch diameter, and it can also serve as a guide for tooth size.
Bevel and miter gears are used for changing rotation direction and are commonly found in hand drills, automobiles, and manufacturing and power plants.