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Aircraft Tool Supply Threaded Drill Bits #40, 30, 21, 12 (4-Pack)

4.3 4.3 out of 5 stars 52 ratings
Currently unavailable.
We don't know when or if this item will be back in stock.
Material Cobalt Steel
Finish Type Black Oxide
Shank Type Straight
Brand Aircraft Tool Supply
Tool Flute Type Threaded

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Product details

  • Package Dimensions ‏ : ‎ 4.1 x 1.9 x 1.4 inches; 0.01 ounces
  • Item model number ‏ : ‎ 4PCBITS
  • Date First Available ‏ : ‎ October 7, 2011
  • Manufacturer ‏ : ‎ Aircraft Tool Supply
  • ASIN ‏ : ‎ B005VR9L3E
  • Customer Reviews:
    4.3 4.3 out of 5 stars 52 ratings

Product Description

Package of four (4) 1/4-28 Threaded Drill Bits in sizes: #40, #30, #21, and #12. Cobalt steel with black oxide finish.

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Customer reviews

4.3 out of 5 stars
4.3 out of 5
52 global ratings

Top reviews from the United States

Danielle M.
5.0 out of 5 stars Bit
Reviewed in the United States on March 17, 2024
Verified Purchase
Good quality for the price 👌
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James T. Jones
5.0 out of 5 stars Drill bits for close quarters operation
Reviewed in the United States on June 26, 2019
Verified Purchase
I only got these drill bits because I was lucky enough to get a drill that uses these bits at an auction. I just wanted to get a sample set of bits for the day I need to use these bits in tight quarters. I've kept your address in case I need to order other sizes.
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mjh999
3.0 out of 5 stars Okay bits, but use very carefully
Reviewed in the United States on January 29, 2016
Verified Purchase
The number 40 bit broke on the first hole, but I have to take credit for the assist rather than totally blaming the bit. It is used in a 90 degree drill attachment, and when it drilled through the 1/8" aluminum, instead of maintaining speed and pulling it out, I let the drill slow and didn't hold enough pressure on the 90 degree drill attachment so it twisted and snapped the bit.

I've been drilling a large number of holes with a normal number 40 bit and it flexes without breaking, so yes, I feel the bit isn't very strong. It wasn't as sharp as my other bits were either, and took about 10 minutes to drill through 1/8" aluminum.

Being more careful with the #30 and #20, I've managed to keep them from twisting and they haven't broken yet.
3 people found this helpful
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robert g thomas
5.0 out of 5 stars So far, so good
Reviewed in the United States on July 29, 2022
Verified Purchase
Worked well on sheet aluminum.
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Greg Sharp
1.0 out of 5 stars Not as Pictured
Reviewed in the United States on September 23, 2022
Verified Purchase
Expected the long version of these bits, as shown in the picture, but received the normal (short) version. This isn't a matter of preference, the tool requires the long version.
2 people found this helpful
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chuck
5.0 out of 5 stars quality product
Reviewed in the United States on August 17, 2019
Verified Purchase
the order meet my expectations.
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James E Ducoing
5.0 out of 5 stars Five Stars
Reviewed in the United States on February 22, 2018
Verified Purchase
These drill bits saved time and effort constructing an RV-4 homebuilt aircraft. Thanks
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charles blatchley
1.0 out of 5 stars Crappy bits
Reviewed in the United States on August 28, 2013
Verified Purchase
Broke all four very easily, might as well be made out of copper very cheap and soft bits. Don't buy.
One person found this helpful
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