Drebo Werkzeug Fabrik Gmbh

Peter Kehrle

Tobias Berg

Martin Stumpp

Alexander Zürn

A drill with a drill flute () includes symmetrical fluted lands () helically extend around a core, wherein grooves () remain between the fluted lands, said grooves having a width () that exceeds the spine thickness or width () of the fluted lands (), and wherein the grooves () comprise a convex core reinforcement () at the groove bottom thereof. The width () of the fluted lands () at the drill head side end () is smaller than at the shank side end () of the drill helix (), and at least increases in certain areas. The core reinforcement () at the drill head side end () is more convex than at the shank side end (), thus has larger radii ().

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Biberach, Germany

Peter Kehrle