Title:
Wear indicator
United States Patent 2657909


Inventors:
Bielstein, Walter J.
Application Number:
US8083449A
Publication Date:
11/03/1953
Filing Date:
03/11/1949
Assignee:
STANDARD OIL DEV CO
Primary Class:
Other Classes:
175/317, 175/393
International Classes:
E21B12/02
View Patent Images:
US Patent References:
2562833Dull bit indicator1951-07-31
2549278Dull bit indicator1951-04-17
2489687Drill bit1949-11-29
2461164Wear indicating attachment for drilling bits1949-02-08
2296183Drill bit1942-09-15
Foreign References:
GB296352A1930-02-27