Bürkle® Mole drill head, combination

For mole there are different drill heads, each designed for very specific soil conditions: Clay and moist soils With narrow flanks that cause the least friction/resistance in the soil. Since moist soils are generally highly cohesive, the soil will still adhere well to the drill bit. Sand With wide flanks and thus further bearing surface in which the sand can hold on well. Coarse sand With extra wide flanks that close the drill even more and thus hold coarse sand soils or very dry soils. Combination Holds both highly cohesive and less cohesive soils. Riverside Very suitable for drilling in hard, crusted soils and soils mixed with fine gravel. Drill blades extend beyond the core bit, greatly minimizing friction. Gravel Drill With slightly curved, angled blades that pull themselves down into the gravel. Any stones are trapped between the drill flanks. The finer soil material (coarse sand with fine gravel) is held inside the drill. Stone catcher The stone catcher can be used to catch and pull out stones that prevent smooth sampling with one of the drill heads.