Patent ID: 6283682
Filing Date: 2001-09-04
Classification: B23B,Y10S,Y10T

Abstract:
A helically fluted twist drill device for cutting materials, said device comprising:a cylindrical core having a first diameter, a longitudinal axis and a first and a second extremity, said second extremity defining a cutting point;at least three portions extending helically outwardly away from said core so that said portions define a second diameter, said portions being arranged such that adjacent portions define therebetween a helical flute;each of said flutes having a flute surface which is of S-shaped configuration when viewed as a cross section disposed normal to said longitudinal axis, said cross section being viewed in a direction from said first towards said second extremity;each of said portions further defining a helical bore connected to a source of a cutting fluid for permitting a flow of the cutting fluid through said bore towards said cutting point, the arrangement being such that in use of said device, the cutting fluid conveys the materials away from said cutting point through each flute;said first diameter having a dimension within a first range which is 20-35% of a dimension of said second diameter; andsaid second extremity of said core and adjacent portions being of cusp-shaped configuration for defining said cutting point so that wandering of the drill device is inhibited.