Making Precise Cuts Using A Router Edge Guide
I think the reason I like this video so much is that it covers the process of using a router edge guide on a project largely unrelated to woodworking as most of us know it. The narrator is building an airplane and requires a complex fiberglass shape to be cut very precisely.
This is the same situation we often face as woodworkers. Using a pattern and a router is a great way to accomplish clean, precise cuts on both sheet stock and solid wood. So although he's demonstrating the technique for cutting fiberglass, everything he's doing applies equally well to cutting wood.
Even though the emphasis is on cutting complex shapes using the pattern, sometimes it's worthwhile to make a pattern for even simple shapes. Take bread boxes as an example. The sides are usually rounded or angled and this may or not be a very complicated cut.
Either way, using a pattern will enable you to make identical left and right ends or even multiple copies with ease. He touches on this idea in the video by demonstrating how to make a perfectly symmetrical part using a pattern of one half of the desired shape - an awesome application for this particular router setup.
The video shows the use of a collar in conjunction with the router edge guide, template, or pattern. This is a great method, but you could also do the same thing using the same finish pass bit with a slightly larger diameter guide bearing.
Whether you choose to use a flush trim bit with a guide bearing or a collar fitted to your router, you'll get a great overall look at the techniques necessary to make smooth, clean, precise cuts of complex shapes.