A Logical Order
Rabbit joints are the recessed outer edges of the end panel, and the side panels fit into them. Make sure they fit together in a logical order.
Before gluing anything together, it’s always a good idea to do a dry assembly to insure correct length and depth of cuts.
Figure 4 provides a look at the baffle.
Notice the dashed line 0.25 of an inch from the edge. This is the area nested in the dado channel on the surrounding parts.
You may consider building wedges with a butt joint on the baffle, but I don’t recommend it.
Regardless of the joinery chosen for the rest of the box, it’s always best to make the baffle the strongest supported area.
Think of it this way: everything is built around the baffle, so dado it in.
Figure 5 is a sample of the side of our enclosure, and it has a cutout for the handle, connector, a dado channel for the baffle, and is rabbited to the top, bottom and sides.
Using 13-ply Baltic Birch 18mm (approximately 0.75-inch) thick plywood, I like to leave 0.50 of an inch of remaining material in the rabbit joint.
This provides strength and makes it easier to calculate the size of the cabinet when designing.
For instance, if you’re building a 24-inch wide enclosure, your rabbits will be 0.50l of an inch thick.
This means that all sides as well as the baffle will be cut to 23 inches in length, making it much easier to calculate your cuts and resulting in fewer mistakes.
After cutting all of the parts, but before cabinet assembly, some “prep” of a few parts is required.
The tuning ports and t-nuts need to be installed, as shown in Figure 6. Recess the ports into the baffle for strength and a clean look.
You can make a baffle with the speaker on the left or right, but pay attention to the side you choose in which to recess the ports.
This determines whether the wedge is oriented as a “lefty” or a “righty”. You’ll need to cut a channel about 0.25 of an inch deep, and large enough to fit the port pipe snuggly in the channel.
Keep in mind that if the port needs to be 4 inches long, don’t forget to compensate for the baffle material in your calculations for its final length.
If the baffle is 0.75 of an inch thick, the tube would be cut to 3.5 inches and recessed into the baffle at 0.25 of an inch, resulting in a port length of 4 inches.
The most common port material to use is PVC pipe, with 0.25-inch wall thickness to help eliminate vibration of the tube.
To affix the ports, use waterproof epoxy and be sure and rough the sides of the PVC so the epoxy has a good surface to adhere to.
Let it dry and clean up the edges on the front with a straight router bit. If you plan to radius the front of the ports, do it at this step, because you can’t get a router in the cabinet after it’s assembled.