Twist drill

A twist drill is made of a carbide alloy and has a pair of helical flutes. The flutes are defined by heel surfaces. Each heel surface bulges, or is formed arcuate, and contacts a margin. The center of the arc is located in the drill. The radius of curvature of each heel surface is from one sixth to...

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Bibliographic Details
Main Authors KOIKE YOSHIFUMI, KURA KIICHIRO, NAKADA KAZUTO, TSUZAKA HIDEO
Format Patent
LanguageEnglish
Published 03.10.2002
Edition7
Subjects
BORING
CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS
ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
ELECTRICITY
GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC
GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS
MACHINE TOOLS
MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
METAL-WORKING NOT OTHERWISE PROVIDED FOR
PERFORMING OPERATIONS
PRINTED CIRCUITS
TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
TECHNICAL SUBJECTS COVERED BY FORMER USPC
TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
TRANSPORTING
TURNING
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Summary:A twist drill is made of a carbide alloy and has a pair of helical flutes. The flutes are defined by heel surfaces. Each heel surface bulges, or is formed arcuate, and contacts a margin. The center of the arc is located in the drill. The radius of curvature of each heel surface is from one sixth to one third of the diameter of a drill portion. Stress that acts on heels due to forming holes is dispersed by the arcuate shape. This improves the rigidity of the twist drill. Also, swarf is reliably cleared and is not stuck in the flutes. This improves the smoothness of the surface of the formed hole.
Bibliography:Application Number: US20010990757