Do yourself a favor and purchase the Hole Hawg right off the bat if you're going to be doing any serious hole boring. I found that normal drills don't come close to having enough torque to bore all the way through the tree round, let alone do it time after time reliably without overheating and breaking down.



I used a very large carbide tipped auger bit (we're way beyond spade bits here since they take too long making dust out of the wood as opposed to larger shavings), and began boring holes into the elm wood, drilling from back to front, stopping approximately 1.5" from the front face of the speaker.



Mark the auger bit with some tape or a zip tie to indicate where to stop so that you drill too far and pop out the front face of the speaker.



To remove the material, I drilled many many holes to create a honeycomb type formation of wood that could then be removed using a hammer and chisel, smaller drill bits to break through the walls, and brute force. Removing the honeycomb structure is truly difficult because it's just so much material, and is connected to the solid wall of the tree round over the honeycombs entire exterior surface. That, coupled with the fact that with the wood was still slightly wet during this process made for some pretty tough fibers that I had to rip through in order to remove the honey comb.



This was by far the hardest part about building speakers made from tree rounds. All in all I'd say that it took even longer to bore out the centers of the tree rounds than it normally takes me to build a rectangular standard speaker enclosure, but, it was well worth it.



The internal volume that I bored out was about a 3/4 of a cubic foot - plenty of air for my 6" driver to move.





