Ive been thinking of how to slot mount my square frame 4" drivers and have come up with the following. Im going to cut a half baffle which will have 16 semi-circles cut in one long pass with a bandsaw (snake shaped) The cut will be larger than half a 4" hole to allow for a router guide. I will then router out 4 pieces of ply, using the template I just made to create 2 complete baffles. Two pieces will be big enough for tweeter mounting. I will glue and screw cross braces every few drivers,to mechanically connect the two baffles. The frames of the drivers should also provide a good connection. This will allow frame to frame mounting.The other option is to cut the holes with a hole saw. The holes will be linked so the bracing is still needed. Two baffles can be cut at once if you fasten them to a sacrifical board with nails. I also shoot brads into the inside of the holes so the cut-outs dont move and stay mounted to the scrap board. This way, you can bore the holes, and not have to remove the plugs.If set up on a drill press, this is a fairly fast process. I use compressed air to clean the holes while cutting to lessen the chances of binding.
Hopefully, I will start this project next week!
taylor