I want to make a miter sled similar to Incra's where you slip a miter gauge into a miter track on the sled.
To do this, I need to attach a runner to a sheet of plywood. No problem since it doesn't have to be exactly parallel to the ply. But on the top of the sled where I plan to put a T-Miter slot it has to be parallel to the runner in order for the miter gauge to be parallel (to the blade) when it's installed. How do I ensure that the T-Miter track and runner area parallel to each other? Incra does this with an aluminum channel that has both the runner and miter slot machined in it.