What is the motor diameter of the Porter Cable 7815 router? Support September 30, 2022 18:54 Updated The motor diameter for the 7815 is 4.2". Related articles Can I use hot water in my pressure washer? What is the decibel rating of the model 7765 rotary hammer? What is the process for sending an invention or idea to someone for consideration? What can cause premature pad failure? Where can I start an online warranty repair claim? Comments 0 comments Please sign in to leave a comment.