HomeMetal & WoodHigh-Speed Drill Bits
High-Speed Drill Bits Aircraft Extension (6" & 12")
Extra-long 6" and 12" HSS drills for deep holes and reaching past obstructions. Tru-Cut and Triumph, in 118° bright and 135° HD black oxide, with cobalt versions, in fractional and number sizes.
Choosing an aircraft extension bit
Aircraft extension drills are long high-speed steel bits for holes a jobber cannot reach: through thick stock, past an obstruction, or deep into an assembly. This range comes in 6" and 12" lengths from Tru-Cut and Triumph, in fractional sizes and number sizes such as #43 and #19.
Two styles dominate. The bright finish bits are 118°. The black oxide bits are 135° HD. Cobalt versions are in the range for tougher material.
Drilling tips
Long bits flex, so start the hole with a shorter bit to set the location, then switch to the extension. Run at low speed, keep the drill square, and back out often to clear chips. Use cutting oil on steel and let the bit cut instead of leaning on it.
Need more than 12"? See the extra-length bits.
Free shipping on orders over $200. Trade accounts can reorder in a click from My Toolbox, or call (833) 438-6657.
Common questions
What are aircraft extension drills used for?
Long holes and hard-to-reach spots: drilling through thick material or past something in the way, where a standard jobber length falls short.
How do I keep a long bit from wandering?
Start with a shorter bit to set the hole, then follow with the extension. Run slowly, keep the drill square to the work, and clear chips often.
Do you have longer bits than 12"?
Yes. The extra-length collection runs from 18" up to 72", in sizes from 1/8" to 1".
Know-how for High-Speed Drill Bits Aircraft Extension (6" & 12")
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Buying for a crew?
Call 833-438-6657, 8 AM to 4 PM MST. We know the parts, not just the part numbers.