Title:
Dull bit indicator
United States Patent 2560328


Inventors:
Bielstein, Walter J.
Application Number:
US9924949A
Publication Date:
07/10/1951
Filing Date:
06/15/1949
Assignee:
STANDARD OIL DEV CO
Primary Class:
Other Classes:
175/242, 175/243, 175/393
International Classes:
E21B12/02
View Patent Images:
US Patent References:
2489687Drill bit1949-11-29
2461164Wear indicating attachment for drilling bits1949-02-08
2239106Well drill1941-04-22