The weight of polymer gears is increasing continuously due to their advantageous properties. This is the reason why in recent years traditional metal gears have been replaced by polymer counterparts in plethora applications. Despite their benefits, their load-carrying capacity is limited. The polymer gears become unable to operate and their teeth generally fail when the load exceeds a defined limit. It is required to explore the limit of polymer materials in gear field. In this work, the gears are manufactured by machine cutting. This paper aims to investigate the limit of load-carrying capacity and the lifetime of POM and PA6 G gears.