Laser cut this as a base for your Makita RP0900 Plunge Router. Everything is adjustable, created 2 SVG files to get started for 1/2" bit and 1" bit.
The screw holes are for 4mm machine screws. Feel free to countersink them once it is cut or you can use this on a CNC and produce larger holes at less depth for the head of the screw.
Variables in OpenSCAD:
$fn= change for the resolution of your circles
outerD=diameter of the largest circle
width=width of the flat edges on the base
centerD=hole for your bit
screwD=diameter of the screw to mount on router