US Patent: 2,148,805
|
| Method of Making Oil Hole Drills
|
|
Patentee:
|
|
| Stuart A. Cogsdill (exact or similar names) - Detroit, Wayne County, MI |
| Manufacturer: |
| Not known to have been produced |
|
|
Patent Dates:
|
| Applied: |
May 09, 1938 |
| Granted: |
Feb. 28, 1939 |
USPTO (New site tip)
Google Patents
Report data errors or omissions to steward
Joel Havens
"Vintage Machinery" entry for Cogsdill Twist Drill Co.
|
|
Description: |
| Claim:
In the formation of an oil hole drill, the step of fanning a generally cylindrical blank having a plurality of spirally arranged angularly spaced flutes in the outer surface thereof and a correspondingly spirally arranged groove in at least, one of the lands between a pair of said flutes, then working at least a portion of the b surface layer of said land first in a generally circumferential direction toward the center of said groove and then radially of said blank while the walls of said groove are totally unsupported, said groove being of sufficient depth whereby the said ; working of said surface layer closes the open side of said groove without completely filling said groove, that portion of said surface thus worked being exclusive of the cutting edge of said land whereby said portion of said land thus worked provides a relief for said drill behind said cutting edge. |
|
