The shank end of the drill bit is the end by which the bit is held and driven.
|Common Shank Types:
3-Flatted Shank - Generally 3 flats designed to allow a strong chuck grip on the shank. Reduces the possibility of the drill slipping in the chuck during tough drill applications.
Reduced Shank - Usually 1/4", 3/8", or 1/2" and are designed to allow a larger diameter drill to be used with a chuck capable of holding only smaller diameter drills.
Tanged Shank - This style of shank is used with a split sleeve drill driver as a replacement for taper shank drills.
|Shank — The part of a drill by which it is held and driven.|
|Washout — The extreme increase at the end of the flute, formed by the grinding wheel or cutter.|
|Web Increase — The web thickness increases in thickness towards the shank to enhance the rigidity of the drill.|
The drill body is that portion of the drill that extends from the shank to outer corners of the cutting lips.
|Drill Body — Portion of the drill extending from the end of the flutes to the outer corner of the cutting lips.|
|Drill Axis — Imaginary straight line that forms the center line of the drill..|
|Back Taper — Slight decrease in diameter from point towards shank, in the body of the drill.|
|Body Diameter Clearance — The portion of the land that has been cut away so it will not bind against the walls of the hole.|
|Neck — The section of reduced diameter between the body and the shank of a drill.|
|Flute Length — The length from the outer corner of the cutting lips at the point (shoulder) to the extreme back end of the flutes. Example Measurement: 2-11/16"|
|Flute —Grooves formed in the body of the drill to provide cutting lips, to permit removal of chips, and to allow cutting fluid to reach the cutting lips.|
|Out-of-Round — Not round. If caused from centerless grinding, the part will usually have 3 lobes.|
|Overall Length — The length from the extreme end of the shank to the extreme end of the drill point.|
Drilling today's wide variety of materials efficiently requires a great variety of drill points, types of web thinning and drill design. The proper use of controlled drill pointing and web thinning can result in substantial savings in drilling cost.
|Point 118° and Split Point 135° —Split point self centering, requires less thrust in drilling harder metal, breaks up chips.|
|Point — The cone shaped cutting end of a drill, made from the ends of the land and web.|
|Cleared Diameter —is measured using a micrometer over the diameter of the cut away portion of the drill lands.|
|Cutting Lip — The cutting edge of a two-flute drill which extends from the chisel edge to the outer edge.|
|Secondary Cutting Edge — The cutting edge formed by the intersection of the face of the notch with the relieved surface of the point, resulting in partial removal of the chisel edge.|
|Drill Diameter — The diameter over the margins of the drill measured at the point.|
|Land — The outer portion of the body between two adjacent flutes.|
|Lip Relief Angle — The relief angle at the outer corner of the lip.|
|Margin — The narrow portion of the land which is not cut away to provide clearance. It stabilizes the drill in the hole.|
|Web Thickness — is measured by using a point micrometer positioned at the point end.|
|Web — The central portion of the body that joins the lands. The extreme end of the web forms the chisel edge on a two-flute drill.|
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