Screw Machine Drill Bits have all the advantages of the 135º split point in a short length, which gives them an exceptional resistance against breakage specially when using a hand held power tool. ( Fractional Sizes: 1/16" to 1/2" by 64ths / Wire Sizes: #1 to #40 ).
Double End Drill Bits have all the advantages of the 135º split point in a short length with a double drilling point. They are used primarily for drilling in sheet metal. (Fractional Sizes: 1/8" and 1/4" / Wire Gauge: #30).
Aircraft Extension Drill Bits have all the advantages of the 135º split point drills in a 6" and 12" overall length. They are specially used for long reach drilling in beams, joists, panels, etc. (Fractional Sizes: 1/8" to 1/2" by 16ths).