So, back to the original question about what MOD means. Well MOD is the ratio of the pitch circle diameter (PCD) to the number of teeth. DP for imperial gears is the number of teeth per one inch of pitch circle diameter. So whilst that may well answer the question, it doesn't really help appreciate the size of a gear.
doer. n. 1. a person or thing that does something or acts in a specified manner: a doer of good. 2. an active or energetic person. 3. a thriving animal, esp a horse. (Ëdu Ér). n.
DOE is a systematic approach to investigation of a system or process. A series of structured tests are designed in which planned changes are made to the input variables of a process or system. The effects of these changes on a pre-defined output are then assessed. DOE was developed by Ronald Fisher in England in 1920 and used in agriculture.