This was a quick job, especially with the Festool rail saw that I borrowed for the task. I can't speak more highly of this tool...great dust collection, straight and quick cuts with no tear-out. What more could I ask for?
Next, I cut six 5' strips on the table saw that make up the interior pieces and all of the sides. I cut one extra just in case of a miscut on the mitre saw.
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Here, I'm dry-fitting the box. As you can see, I biscuited the exterior. This makes gluing a lot faster and more accurate. When gluing, the pieces tend to slip a bit if the clamps aren't aligned perfectly, and biscuits, dowels, or dominos help everything line up.
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Everything fit perfectly, and you can see the added bracing in this picture.
Next step, wiring, installing the binding posts, final gluing and installing the driver.