2015 Product Catalog

GLOSSARY TECHNICAL TERMS

(A) TIP DIAMETER

Drill bit diameter at tip. (B) SHANK DIAMETER Drill bit diameter at shank end. Also includes 3/8" reduction diameter. (C) DRILL LENGTH The length of drill bit from shank end surface to the leading edge of the primary chisel. (measured at the outer diameter) (D) TIP THICKNESS Thickness of the web at the point. (unless another specific location is indicated) (E) RELIEVED DIAMETER Diameter of the drill bit body that has been cut away to minimize friction from the hole. (F) MARGIN WIDTH Width of the non-relieved portion of the major diameter of the drill bit. (G) CHISEL ANGLE Included angle between the chisel edge and the leading edge of the cutting lip, as viewed from the front end of the drill. (H) SECONDARY CHISEL ANGLE Included angle formed by the intersection of the cutting edge and the face of the notch with the relief sur- face of the point, resulting in partial removal of the primary chisel edge. (applies to split point geometry only) (I) POINT ANGLE The angle included between the cutting lips projected on a plain parallel to the cutting axis and parallel to the cutting lips. In form this angle resembles a cone, but it departs from a true cone to furnish clearance behind the cutting lips. (J) LIP RELIEF ANGLE The clearance angle of the cutting lips. Measured by projection onto a plain tangent to the periphery at the outer corner of the lip. The lip relief angle is usually measured across the margins of a twist drill. (K) SECONDARY CLEARANCE ANGLE The included angle generated from the clearance operation for the secondary cutting edge. (L) FLUTE LENGTH Length of heliocal flute measured from outer edge of cutting lip to back leadout edge of the flute. (M) CUTTING LENGTH Length of relieved diameter measured from outer edge of cutting lip to back lead out edge of the relieved diameter grind. (N) WEB The central portion of the body that joins the lands. Extreme end of the web forms the chisel edge on a two flute drill bit. (O) LAND WIDTH Peripheral portion of the body between adjacent flutes. (P) RADIUS IN NOTCH Clearance angle of the cutting lips. Measured by faster, more efficient chip removal.

NUT DRIVER TECHNICAL

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