5 piece center drill set High speed steel and ground ~Plain style~ Used for centering work ends, where the work piece is to be revolved on machine centers.~60° countersink angle fits all standard centers.~Size#1 : Body Diameter 1/8:, Drill Diameter 3/64", Overall Length 1 1/4" ~ Size#2 : Body Diameter 3/16:, Drill Diameter 5/64", Overall Length 1 7/8" ~ Size#3 : Body Diameter 1/4:, Drill Diameter 7/64", Overall Length 2" ~ Size#4 : Body Diameter 5/16:, Drill Diameter 1/8", Overall Length 2 1/8" ~ Size#5 : Body Diameter 7/16:, Drill Diameter 3/16", Overall Length 2 3/4".