Jaegers 6" f/10 "GJD" OTA Construction - Knife-Edge Baffles (2nd knife-edge measured - front)
 

Checking and verifying knife-edge opening in second baffle - 20 (Click to see an enlarged image.)

 
After using the laminate trimmer/ router to make the knife edge in the second baffle, I measure the diameter and saw that I had produced a near perfect 3" diameter knife-edge opening in its center. Exactly what I was hoping for, per the specs.