Tree Speakers

Step 5 Drilling

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.

Comments

[Dr. Science]

Wouldn't a person just use a router and probably varying levels of depth (like 2 inches) at a time, obviously using a jig to keep it all the same, using a deeper bit each time for every 2 inches of depth. The opening could take on a square or rectangular shape if wanted, for example. The same way the opening for the drivers should be made. The driver's particular pattern of their "frames" should be counter sunk about a quarter of an inch for a perfect fit. Two reasons: (1) for looks, adds value and craftsmanship (plus, it's pretty easy to do) and (2) it "seats" the driver to the "baffle", that is, in this case, the tree trunk making it become one with both. The object of the driver, the "transducer", is to make active, and, as active as it most possibly can, the baffle. The more immoveable the baffle, the more the baffle can be controlled. While this is being done, it's nice to know that the driver is perfectly mounted, on it's own plane, not warped or rattling against a non-prepped perfectly flat baffle (tree trunk).

While you're at it, design into the routed out area for the frame, countersink 4 anchors aligned perfectly to receive high tech looking machine threaded fasteners, for both the woofer and the tweeter.

And really, don't stop there. Find a decent self amplified - properly cross-over-ed sub drive amplifier that's piggy backed off your pictured receiver / amplifier, made the same way, same proportioned dimensions, with a larger tree trunk section. Design it to allow the room to be part of the speaker.

Lastly, choose the right driver. A really friendly vendor for this might be Parts Express out in Ohio. I live in Montana and have done a lot of business with these folks. Good people. They sell a type of product for every taste. See:
http://www.parts-express.com/home.cfm

One might consider thinly sawing a much larger section of tree for the very high frequency driver, like a nice soft dome tweeter for those really sweet highs.. Mount the tweeter as close to center as possible for best dispersion, on the same wall (plane). Cool idea!

[phildc]

I think countersinking the surface for the frame is a great idea, and you'd need a router for that, but where would you get router bits long enough to mill out a deep enough hole, or a hand held router with strong enough bearings to handle them? Also, auger bits remove material (albeit vertically) much more easily than any router bit I know of. I'd do the same as in the instructable, but use a heavy drill press.

[chucklesncreme]

Hey, something else that might speed up drilling time could be to build a small fire on top of the log and let it burn through. Kind of like making a dugout canoe.

[ArlisVDV]

  I often see chunks of elm like this with the center rotted out.  A large dutchman (plug) in the front and back would save all the hollowing work.  I would think if you worked carefully the plug would not be noticed.  I say this knowing exactly what it takes to hollow a log out as I spent many hours making a planter using your method.

[noahw]

Sounds good, but you knew this question was coming - how do you make a dutchman for a piece of wood like this? 

Planters in tree rounds - nice.

[ArlisVDV]

I was thinking either trace the opening from the inside on to a solid cutoff  piece.
Or take a cutoff piece and trim it up and trace it on the hollowed piece letting it in with a chisel.  Using a lathe like someone else mentioned would work beautifully.  But I don't have a lathe.

[RHSeabrook]

What about using an auger bit in the circular pattern you show in the images, and then use a saws all with a 10 inch blade to cut around the outer ring of holes?  This would give you the depth or close to it and if you have to cut deeper than 10 inches, change the blade to a shorter one and go again deeper inside the trunk.  Just a brainstorm. :)

[noahw]

That would have helped!  

I didn't use a sawzall but I really should have.  I ended doing about as much with a hammer and large chisel. 

Knocking out the honeycomb at the bottom - the one place you can't get to with a sawzall or a chisel is really the tough part though that just requires some brute strength.