US Patent: 542,223
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| Drilling Tool
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Patentee:
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| Moses C. Johnson (exact or similar names) - Hartford, Hartford County, CT |
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Patent Dates:
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| Applied: |
Apr. 19, 1893 |
| Granted: |
Jul. 02, 1895 |
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Joel Havens
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Description: |
| This patent is for the design of the flutes for a Twist Drill. The original Twist-Drill patent in 1863, was #38,119 by Stephen Ambrose Morse. It was manufactured by the Morse Twist Drill & Machine Co. of New Bedford, MA.
Abstract:
The invention relates to the class of boring- tools that are commonly known as "twist-drills."
The object of the invention is to produce a drill having two spiral grooves that are stiff and strong, so as to resist any tendency to untwist, bend, or break; that will always, until it is worn down to the shank, maintain lips having a constant cutting angle of maximum efficiency to properly raise the chips without an expenditure of excessive force, and that will freely clear itself of chips without unnecessary friction. To this end the invention resides in a twist- drill which has two parallel spiral grooves of uniform pitch and equal width from end to end, but of gradually-decreasing depth from point to shank, whereby the lands are of equal width, the lines of the cutting-edges of the lands are uniform in pitch and parallel with the pitch of the grooves, and the web gradually increases in thickness from point to shank.
Claim:
A boring tool having a shank anti a point, with parallel grooves of decreasing depth extending full width on a spiral of uniform pitch from point to shank, and parallel lands extending full width on a spiral of uniform pitch from point to shank, the edges of the lands and the center line of the grooves being parallel and on the same pitch from end to end. |
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