Societe Nationale D'etude Et De Construction De Moteurs D'aviation

Jean Pierre Leboulanger

Maurice Jean Cabaret

Gilles Rouge

Michel Lebrun

Daniel Marcel Lavocat

Bernard Gilbert Roy

Francedillaois Masson

Christian Thierry Daude

The cutting end or head of a helically grooved drill bit is of generally hemispherical shape and has four cutting lips, two of which are disposed in end-to-end relationship at the point S of the bit. The cutting angle of the edge of each lip is evolutive, varying from 0.degree. at the point S to a value, determined experimentally in accordance with the material to be machined, at a position P at the intersection of the cutting edge with the end of the outer diameter d of the bit.

Drill bit having a hemispherical head with an evolutive cut

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Chartrettes, France

Jean Pierre Leboulanger