little hard to get). you want to run the router around the inside of your sled with the base plate making contact with all edges. this will give you a hole big enough to run your router through (and make minor adjustments) when making passes on your material and not have to worry about it chewing up your sled (well, after you chew it up here).
after you have the slot cut into your material you’re finished and ready to use the sled. i might add a poly coat or two to the inside just to add a smoother surface for the passes, otherwise, you have a jig that can now 