For routing out the electronics cavity, I made a template of the body of my Gibson Melody Maker guitar out of a piece of 1/4 inch plywood. One thing I noticed on the Melody Maker, was that the electronics cavity seemed a bit too small. So I made mine a bit bigger.The depth of the controls cavity is a little over an inch.

Next I placed the template on top of the guitar body and clamped it down. Then I used the Forstner bit to rough out the cavity as shown in the photo on the right. Again, I made sure that the depth of the forstner bit was less than the final depth of the electronics cavity. The photo on the right shows the cavity before using the router.

Notice that on the template for the guitar body, there are cutouts for the pickup cavities. After I made this template, I changed my mind about using this template to route out the pickup cavities.

Like I mentioned earlier, Its important to run the router in the proper direction of the template. Since this is known as an inner cutout, and most routers spin the bit in a clockwise direction, you will need to move the router in a clockwise rotation when routing the pickup cavity.

Here is a photo of the guitar body with the completed Controls Cavity.