You could route a circle Larger than the 690 base plate, in some scrap material.
Make the circle large enough so the 690 base will fit in the center of the large circle.
Remember to allow for the diameter of the bit. Then you will be able to use the large circle as a template to route your two 1/2" plywood pieces. They could be cut together, by temporary nails or double back tape. Good luck.
Richard wey
Make the circle large enough so the 690 base will fit in the center of the large circle.
Remember to allow for the diameter of the bit. Then you will be able to use the large circle as a template to route your two 1/2" plywood pieces. They could be cut together, by temporary nails or double back tape. Good luck.
Richard wey