TY  - SER
TI  - 2007 Drill bit classifier
PY  - 2007///
CY  - 
PB  - 
N2  - List of major manufacturers drilling bits to aid drilling supervisors and engineers in fiel selection. While this listing has been published annually for many years, changes from year to year are significant. Prior to ordering, users should consult the manufacturer to verify availability and specifications
ER  -