6 Inch Aircraft Extension Drills are designed for drilling holes in aircraft assembly work where long reach is needed – Ideal for drilling aluminum and low to medium steel alloys – Drills will not walk on workpiece due to 135° self-centering split point – Flute length is the same as a standard jobber drill – Black Oxide Treated High Speed Steel enhances heat resistance and longer tool life – Spring tempered shanks prevent permanent bending when drilling holes not in direct alignment – High Speed Steel