Although you may not realize it, gears are all around you. They are used in railroads, cars, space shuttles, wartime equipment and even on top of the Freedom Tower in New York City. Although gears are all around you, you may not be familiar with everything there is to know about them. Below are a few facts that will help you to better understand them.

Gears were one of the first instruments to transmit motion
There are quite a few objects that allow motion to be transmitted, gears included. However, gears are actually the oldest of these objects. Despite gears being one of the oldest tools used for motion, they are still commonly used today.

Different types of gears have differences in their teeth
When you think about a gear, you may immediately think of their teeth, which allow them to transmit motion. These teeth are cut into these gears using many gear cutting processes but most commonly gear hobbing is used. Gear hobbing uses a tool called a hob to cut teeth into each gear. Despite it being a relatively inexpensive process, gear hobbing is actually quite accurate. Accuracy during this process is highly important, as each gear requires differences in its teeth. For example, straight bevel gears have straight teeth, while spiral bevel gears have curved teeth.

Gears can be made from different materials
While this fact may be less surprising than the others, many people may not realize that gears are made from different materials. While there are many options for materials, cast iron is typically the most common, especially in bevel gears. Cast iron does not wear easily and is very durable, making it a great material to use.

Railroad typically have rack and pinion gears
You may not be familiar with rack and pinion gears; however, they are commonly used on railroads. One part of this type of gear is the rack, which is a toothed strip. The pinion is the circular gear that is used with the rack. While many gears are used on railroads, rack and pinion gears are commonly used when operating locomotives.

Bevel gears have many uses
Bevel gears, which are shaped like right circular cones, are used in many types of equipment. Similar to rack and pinion gears, bevel gears can also be used in train equipment. However, they are also commonly used in cars, power plants and even painting presses. This is likely because bevel gears are relatively versatile because the operating angle of the gears are usually able to be adjusted.

While gears can be found in equipment that you use every day, you may not have known some of these facts about them. Can you think of any more unusual facts about gears that others might not know? Let us know in the comments!