Abstract
Up to the present, authors have sometimes researched in the field for chain conveyor water scoop wheel with rectangular plates remained in People's republic of China. At that time, each dimension of the parts of the water wheel was measured. In the mechanical engineering field, the unit of the length is used "millimeter" with no declaration. However, it flashed by chance when drawing was performed from the measurement value. Parts are sure to be made from the unit of "里・丈・尺・寸・分・厘・毫" from which use is prohibited now if it is a sphere of the culture of the Chinese character. Then, authors analogized the unit of length in manufacturing standards from the measurement values of the parts of the water wheel.
