1/4 inch - 1/2 inch x 12 inch HSS Aircraft Extension Drill Bit Set, Plastic Case Pouch, Qualtech, Poua/cx12 LRT74_M3035

Product details:

Manufactured to Aerospace Standard 907. The 135 degree split point is self-centering and reduces thrust. Ideal for drilling in mild steel where extra length for reach is required. They have a black oxide surface treatment that is abrasion resistant, reduces chip welding and improves chip flow. Sizes smaller than 1/16 and #52 have the 118 degree standard point. Sizes included are 1/4 inch, 5/16 inch, 3/8 inch, 7/17 inch and 1/2 inch with overall length of 12 inch