They are general purpose drills with increased cutting length. Taper Shank Drills have a tanged conical shank to fit directly into the tapered holes of drill press spindles, driving sleeves or sockets. They are designed for general purpose drilling in ferrous or non-ferrous metals.
Parallel shank drills :
The hss twist drill bits for drilling through stainless are a fully grounded twist drill that comes with a right flute. This drill bit is perfect for general drilling for HRC 28 hardness steel, and have excellent performance for hard-working steel, HRC above 28.