An embedment device (60) includes a first integrally formed elongate shaft (62) rotatably secured to the support frame (12) and having a first plurality of axially spaced disks (64) axially fixed to the first shaft, a second integrally formed elongate shaft (66) rotatably secured to the support frame and having a second plurality of axially spaced disks (68) axially fixed to the second shaft, the first shaft being disposed relative to the second shaft to be horizontally aligned and so that the disks intermesh with each other, and wherein, when viewed from the side, peripheries of the first and second pluralities of disks overlap each other.