Cut gears, or straight-cut gears, are perhaps the most common type of gear, used in more mechanical applications than any other. Also referred to as spur gears because of their shape, cut gears are disc-shaped gears with measured and calibrated teeth, or cogs. The cogs in cut gears are spaced equally around the radius of the gear disc. They project straight outward from the axis of the gear disc, though the sides of each tooth are usually cut at slight angles to ensure smooth gear integration.
In almost any mechanical device that requires the transfer of some amount of power from one angle to another or from one speed to another, the use of gears is implemented to carry out the task. In fact, gears are mechanical devices all their own, used to create, transfer, and modify power, speed, and torque. The gear has been a tool utilized in mechanics since as far back in history as 50 A.D.
Throughout this time, gears have not undergone significant alterations other than size and fabrication material. The earliest gears were fashioned from different types of wood. Some were strengthened with resins and pitch coatings to prevent weathering and splitting.
Since the advancement of fabrication technologies began hundreds of years ago, gears have become stronger, more durable, more precise. Cut gears were originally the only type of gear, but today technology has expanded from the cut gear to dozens of different gear types, each with its own specific purpose. The straight-cut gear itself has undergone moderate changes with the onset of different technologies, with the most noticeable change stemming from the realization that slightly angling each side of the cut gear’s teeth provided a much smoother transition of power from one gear to another while also preventing binding of the gear teeth as the gear rotates.
As different mechanical applications came about, alterations to the design of the gear had to be made to allow the mechanisms to work properly. Different gear designs have been created and utilized in hundreds of different forms and fashions, no matter what material the gear is fashioned from. Plastics, composites, stone, and metals all play a role in the fabrication of different gears depending on the application they are designed to take part in. With the rate of advancement in both technology and mechanical applications, they will be utilized for a long time to come.