Routing dadoes and grooves with a shopmade T-square works great. The setup is quick and easy. But most T-squares are usually made for a specific diameter of router bit. The auxiliary router base and T-square you see here solves that problem. This allows me to accurately position and rout four sizes of dadoes and grooves by simply rotating the router.
To use the jig, align the notch in the cleat with your layout mark. Butt the appropriate edge of the baseplate against the fence and make the cut.