To investigate how manufacturing errors affect the gear set, a method is developed to calculate the contact stress of a gear set with pitch and involute incline errors. The method is parametric, and a hybrid model is used to model the gear stiffness. Contact outside the line of action is considered.A numerical example is used to show how manufacturing errors can change the contact pressure and cause tip contact, in spite of tip relief, resulting in high contact pressure. A threshold for maximum allowable torque of the gear set due to the specified errors is found