Router Dado Jig
In the course of my work as a contractor, I often need to build cabinets and bookshelves on site – without the luxury of shop tools. I gave up on the flimsy router fence supplied with the machine and made the jig shown in the sketch. The router base now slides between two fixed aluminum guides with no chance of slippage or accident. I used some salvaged track, but aluminum angle ought to work, as well. I attached the piece of 1" scrap at one end to square up the jig against the cabinet sides.
This is a classic router dado jig. The cool part is that when you run your 3/4" router bit through the 1" block – or fence – at the end, positioning the jig is easy. You just mark where you want the dado on your workpiece, and then line up the notch made by the bit through the jig's fence. Equipped with a couple out-riggers, this jig also works for flattening stock that's too wide for your jointer.