For a bosch routing table. This insert has a 42 mm opening. This gives about a 6 mm clearance on a 30 mm corner bit that I have.

As a CAD exercise I made the bottom have ribs for strength like the OEM insert (red one in the picture). Mine came out a little stiff er than the OEM one so the ribs work. It drops right in and has zero wiggle.

I've attached the Fusion 360 project, which is fully parameterized. Go to Modify -> Change Parameters to change insert diameter, bit diameter, clearance, lip, rib dimensions.