The AGMA Mill Gearing Committee completed AGMA 6014 for grinding mill and kiln service gear rating. The approach the committee took in the development of this standard to determine the content is reviewed. Through a review of previous standards, the performance history of applications for long life (over 20 years), and considering the large gear size, the committee achieved consensus on a rating method, which was derived from ANSI/AGMA 2001-D04. A factor comparison between 6014 and 2001 is presented, as well as their interaction, to explain the goal of the committee to develop a document that reflects actual field experience of in-service operating gear sets.