The stitch drilling segment is expected to hold the largest share of the global diamond core drilling market during the ...

That leaves a round disk or core of material. Step bits function as multiple drill bits in a single tool. Instead of a cylinder, these are cone-shaped, with a distinctive stair-step profile.

Barbante also directs the Polar Science Institute at Italy's National Research Council.The same team previously drilled a core about 800,000 years old. The latest drilling went about 1.7 miles ...