Fig. 1 illustrates the components of a HSA used with a
pilot bit for hole advancement using a center-inner rod system.
Figs. 2 and 3 illustrate HSA equipped for soil sampling in
either a rod-type or wireline system. Hollow-stem auger
systems consist of rotating outer HSA and a cutter head
assembly, with either a center pilot bit or a nonrotating inner
sample barrel with a smooth cutting shoe.