Cogs. Cogs for use in a gearing system. These cogs have teeth cut parallel to the axis and are also known as spur gears. Cogs are used to transmit rotational motion from one shaft in a machine to another. The speed of rotation can be changed by connecting cogs with different numbers of teeth. If the driven cog has more teeth than the driving cog the speed will reduce; if the driven cog has fewer teeth, the rotational speed will increase.
