501-6 aircraft extension drill bits are manufactured from premium High Speed steel and are suitable for drilling many materials including steels, aluminum and stainless steel. They have a long overall length, together with a short flute length, which is recommended for stable drilling in those hard to reach areas. They are available in many wire gauge sizes from 60 to 1 and come with a steam oxide finish which helps prevent workpiece material from sticking to the cutting surfaces of the tool so you get a clean and accurate result. 501-6 aircraft extension drill bits are manufactured to NAS907 type B standard and come with a 135 degree split point to help self-centering and reduce the push force required.