This is how I cut speaker holes. The template I have bolted to the bottom of my router is my own invention. I have found it is important to NOT cut right through. I did once and of course the router was then free to move because I had cut the focus of my locus away from the rest of my job.
The deep bevel is so that the speakers, once mounted, do not find themselves in a 22mm deep tube. For 5″ drivers the ‘tube’ appears significant. The box needs to be as inert as possible and to return as little as possible back through the cone from reflections inside the box. The bevel lets the energy from the back of the cone radiate out into the box which I will eventually stuff with polyester and some bumpy foam.
As I have said before, this is not a ‘how to’ guide, just a diary. That said, the plunge router is a dangerous tool. Adding home made jigs can’t help I wouldn’t think 🙂
The box was trimmed flush with the router (jig removed) after the glue dried. I am loving a new (and toxic) polyurethane glue. It goes yellow and foamy and looks like artificial honeycomb. However it appears to be crazy strong and is sticky from the start. I have found normal PVA white glue greases everything and it all tries to slide apart during assembly.
Benjamin's Bench 