561 - Bright, Fractional, wire & letter sizes
561P - Tin Coated, Fractional & wire sizes
563 - Aircraft, Fractional, wire & letter sizes
6563 - Aircraft Cobalt, Fractional, wire & letter sizes
To get the best performance and longest life out of your Nachi drills we have provided speed and feed calculators specific to your drill and the material that you are cutting as a starting point.