Sub Project: A Baffling Experience

I spent today working on the dual baffles for the subwoofers by trimming away some excess for a better fit, and making the cutouts for the drivers. Above is a picture of the circle jig setup. I just measured from the edge of the router bit to a point on the jig equal to one radius of the hole I was cutting, and drilled a hole for the pivot screw.

Here's the first cut. I tried to do it a little too quickly by setting the router bit a little too deep at first, which made it tough going for the first pass. For the next cuts I made three passes instead of two and the router didn't sound as angry since it didn't have to chew through quite as much wood on each pass (this Baltic Birch is tough). The following picture was taken halfway through the first pass, which is about 1/4" deep.

After all of the cuts were made, I was left with a handsome set of double baffles. The inner baffle has a lip for the driver to sit in, and allows for holes to accept screws to hold the driver in. The outer baffle recesses the driver so it sits flush with the outside of the cabinet. Together they add some extra rigidity to the enclosure, so I won't be putting any back to front bracing.

And below you can see how the driver fits in. The holes came out really well, except for a small bump at the end of the final pass. Since the jig was attached to the part that was getting cut away, it didn't finish perfectly. Thankfully the bumps were pretty small, and a couple minutes with some sandpaper knocked them down flush for a perfect fit.

In the next couple of days I'll drill the holes for the driver screws and insert some hurricane nuts, then I'll glue the double baffles together, and finally start gluing the cabinet together.

Sub Project: Circle Jig Test

I got a chance to test out the circle jig, and make sure I made any mistakes on my scrap pieces before going at the good ones. Above you can see that I modified the jig a little bit as a result of the test. I added a couple more holes to allow sawdust to flow through, and I widened the hole for the router bit so the collet could fit all the way through. Before, the bit wouldn't go deep enough to cut all the way through the 3/4" plywood.

I learned a couple other valuable lessons in the process: the first being that I shouldn't try to use the drill to back out the pivot screw. It just snapped off flush with the surface and I never managed to get it back out. I ended up just putting in another screw, which slightly shifted the circle.

I also learned that I should be careful about drilling the hole to allow the router bit to pass through. I drilled right where the edge should have been, and ended up with a little bump in the hole (seen in the bottom right in the image above). In spite of those mishaps, it turned out really well.

The hole measured exactly 13-7/8" in diameter, and it fits like a glove as the cutout for the subwoofer. Next up I need to trim a few pieces then cut the actual cutouts in the baffles before I can start gluing things together.

Sub Project: Router Circle Jig

In preparation for making the cutouts in the baffles, I got to work making a circle jig for my router. I went to several hardware stores and none of them seemed to have what I was looking for, so I just got a cheap 1/4" piece of MDF (conveniently the same thickness as the base plate for my router) and had them cut it into strips that I could use for my own circle jig. First I marked the holes for the screws that held the stock base plate onto the router.

Next I took the project outdoors where I drilled holes large enough for the base plate screws to go through. I also drilled a big 1/2" hole in the center to let the router bit pass through.

After a couple minutes I had my holes and was ready to mount it to the router, or so I thought. I had forgotten that the screws were beveled, so I had to go back and countersink the screw holes so that they would sit flush with the bottom of the jig to keep it from scratching the baffle when I cut the circle.

As you can see from the following picture, I messed up one of the first holes when I tried to countersink it, and it ended up going all the way through. I just shifted the base plate, redrew the template and started over. It ended up working great. Now all I need to do to finish this off is measure from the far edge of the router bit to the point where I want to pivot and I'll be good to go to start making some perfect circles.