For easy fixation of the workpiece to the table the table has 14 mm deep holes with M5 thread. 7 x 7 and 6 x 6 holes in a checkerboard pattern at 5 cm distances, so 85 in total.
These holes were created with the router itself: the 15 mm aluminum table was placed on top of the temporary MDF table and 3mm deep holes were milled.
The Estlcam software that I use has a nice ‘Tile’ function for this: only the two bottomleft holes of the 7 x 7 and 6 x 6 pattern were drawn in Inkscape and via DXF exported to Estlcam.
In Estlcam the tile function was used to define the complete pattern of 85 holes and generate the G-code.
For M5 thread the hole diameter must be 4.2mm. I used a 1/8 inch single flute bit to mill them at accurate locations, but only 3 mm deep and decided to go for a different solution to drill them to their final depth.
The Kress mounting bracket has a standard 42 mm diameter and so has my Skill drill.
So I temporarily removed the Kress mill and replaced it with the Skill drill to drill the milled holes to the full 14 mm depth.