Chicago-Latrobe F, High Speed Steel, Jobber Drill Bit, 4-1/8" Overall Length, Black Oxide Drill Bit Finish

These drill bits come in standard letter sizes. The trade letter size for each drill bit indicates its compatibility with other tools that have the same trade letter size. The bits have a black-oxide finish that retains lubricants to improve the bits' wear resistance and chip flow. Black-oxide bits should only be used for drilling ferrous metals. These bits have spiral flutes that evacuate chips as the bits drill into a workpiece, and they have a straight shank that installs into a drill chuck or similar toolholder.