Wrap the towel around the middle of the broom handle.
Place the middle of the broom handle, wrapped in the towel, into the vise. Close the vise until the broom handle is held securely. Do not over-tighten the vise or you risk cracking the wood.
Place the die over the bottom end of the broom handle. Grasp the handles of the die and rotate the die clockwise, twisting the die down onto the shaft.
Continue twisting the die onto the broom handle until the die has cut the threads to a sufficient depth to accept the broom head.