US Patent: 3,564,945
|
| Drill
|
|
Patentee:
|
|
| Harry Edwin Bradley (exact or similar names) - London, England |
| Manufacturer: |
| Not known to have been produced |
|
|
Patent Dates:
|
| Granted: |
Feb. 23, 1971 |
USPTO (New site tip)
Google Patents
Report data errors or omissions to steward
Jeff Joslin
|
|
Description: |
| This is a sheet metal drill bit that moved the state of the art a small step closer to the ideal, which arrived in the 1973 patent 3,758,222. This design uses a separate pilot bit which would prove to be a needless complication, and also has three cutting edges whereas a single cutting edge would prove to work better because it was easier to control.A British patent was applied for in 1967 but no such patent was ever issued. Canada patent CA-883,543 was issued in 1971 for the same invention. |
|
