The diameter of the wood I used was slightly greater than the inside diameter of the head. I sanded it down to a snug fit, sawed a slit in the top, put the head back on, hammered a wedge down the slit, and then since the top of the head screws off, I left that off and poured epoxy into the head to just double make sure everything stayed together, and then screwed the top back onto the head.
Also it's a total of only 19 inches long and weighs about 2.5 lbs. Handles exactly like my tomahawk actually. The flanges are actually made from what was a union joint, which is a large nut used to join twould sections of pipe. I used an angle grinder to cut out parts of the nut to leave the flanges.