Irwin 66716 Black Oxide High-S...
IN STOCK (leaves warehouse same day if ordered before 3pm ET)
$3.57
Irwin 66716 Black Oxide High-Speed Steel Twist Drill Bit with Aircraft Extension

Irwin 66716 Black Oxide High-Speed Steel Twist Drill Bit with Aircraft Extension

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Model: 66716

In Stock (leaves warehouse same day if ordered before 3pm ET)

$3.57
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Irwin 66716 Black Oxide High-Speed Steel Twist Drill Bit with Aircraft Extension

The Irwin 66716 Black Oxide High-Speed Steel Twist Drill Bit with Aircraft Extension is engineered for jobs that need more reach than a standard-length twist bit can deliver, and this family is available in sizes from 1/4" to 7/16" to match a range of extended-reach drilling tasks. Machined from premium M-2 high-speed steel, each bit offers increased durability for repeated use, while the black oxide finish resists corrosion and helps protect the cutting edge over time. A 135-degree split-point tip starts drilling immediately with less force and eliminates "walking" across the work surface, helping users achieve accurate hole placement on the first pass. The aircraft-style extension is purpose-built for extended-reach tasks and is not recommended for deep drilling applications.

Key Features

  • Size Range: Available in 1/4" to 7/16" to suit a variety of extended-reach drilling applications.
  • Durable Construction: Made from premium M-2 high-speed steel for increased durability in demanding drilling tasks.
  • Corrosion-Resistant Finish: Black oxide finish resists corrosion and helps extend the working life of the bit.
  • 135° Split-Point Tip: Starts drilling immediately with less force and eliminates "walking" across the work surface for more accurate hole placement.
  • Extended Reach: Aircraft extension design is ideal for applications requiring extended reach beyond standard-length bits.
  • Bit Type: Twist bit configuration suited for general-purpose drilling tasks.
  • Usage Note: Not recommended for deep drilling applications; intended for extended-reach, standard-depth work.

Technical Specifications

  • Bit Type: Twist
  • Power Source: Non-Energy Using
  • Warranty: NLW
  • Claims Needed: No
  • Battery Included: No
  • Country of Origin: China

Typical Applications

  • Extended-Reach Drilling Applications
  • Metalworking and Fabrication Tasks
  • General-Purpose Twist-Bit Drilling
  • Workshop and Job-Site Use

Why Irwin?

Irwin builds this drill bit family from premium M-2 high-speed steel with a corrosion-resistant black oxide finish, backed by a 135° split-point tip engineered to start cleanly and stay on target without walking. Available in sizes from 1/4" to 7/16", the aircraft extension design gives professionals and DIYers the extended reach needed for hard-to-access work, making it a dependable choice for twist-bit drilling tasks where standard-length bits fall short.

Manufacturer Resources

Product Specs

Warranty:
NLW
Bit Type:
Twist
Claims Needed:
No
Individual Vs. Set (Syndigo):
INDIVIDUAL
Product Material Group:
METAL
Battery Included:
No
Power Source:
NON-ENERGY USING
list_batch:
IRW-20260923
Product Type:
Twist Drill Bit
Product Finish:
Black Oxide
Department:
Electrical
Product Subgroup:
Drill & Driver Bits
Product Material:
High-Speed Steel
Product Width:
2 inches
Product Group:
Power Tools & Accessories
Product Length:
8.1 in

Irwin 66716 – Frequently Asked Questions

1) What sizes does the Irwin 66716 aircraft extension drill bit come in?
Two diameters are offered in this Irwin black oxide aircraft-extension twist bit family: 1/4 inch (part number 66716) and 7/16 inch (part number 66728). If you need a diameter between those, it isn't offered in this extension bit.
2) Can I use an aircraft extension bit for deep hole drilling through thick timber?
No. The aircraft-style extension is built to reach into tight or obstructed spots, not to bore deep holes, and Irwin specifically does not recommend it for deep drilling. Use it for standard-depth holes where a regular jobber-length bit can't physically reach, such as drilling through a stud bay or behind ductwork. For deep boring in wood, an auger or a bellhanger bit is the right tool.
3) I'm an electrician drilling through a wall cavity to pull cable. Is this the right Irwin bit?
For reaching past an obstruction to put a standard-depth hole in metal framing or a plate, yes, that's exactly what the aircraft extension is for, and Irwin groups it with electrical work. What it will not do is bore the long deep runs through stacked plates or multiple studs, since it isn't recommended for deep drilling. For those pulls you want a flex bellhanger or auger bit instead.
4) Will this Irwin bit drill steel, or is it only for wood?
It cuts metal. The bit is machined from M-2 high-speed steel, which is the standard grade for drilling mild steel, aluminum and other metals, and Irwin lists metalworking and fabrication among its applications. It also works fine as a general-purpose twist bit in wood and plastics.
5) What does the 135 degree split point actually do on a drill bit?
A 135-degree split point is self-centering. It bites into the surface immediately under less thrust and stops the bit from walking or skating, so you can place a hole accurately without center-punching first. On an extension bit that matters more than usual, because the long shank flexes and a standard 118-degree chisel point would wander before it cut.
6) Does the Irwin 66716 come as a single bit or in a set?
It ships as an individual bit, not a set, and each size carries its own part number: 66716 for the 1/4 inch and 66728 for the 7/16 inch. If you want both diameters on the truck, order them separately.
7) Is the black oxide coating on this Irwin bit worth anything on a job site, or is it just cosmetic?
It's functional. The black oxide finish resists corrosion, which is what keeps a bit usable after it has lived in a damp van or a site gang box, and it helps protect the cutting edge over the life of the bit. It is not a hardness coating like titanium nitride, so sharpening and feed rate still govern how long it cuts.
8) Will this bit fit a standard cordless drill chuck?
Yes. It's a round-shank twist bit in 1/4 inch and 7/16 inch diameters, so it chucks into any standard three-jaw keyless or keyed chuck. It's a manual cutting tool with no battery or power components of its own, so there's nothing to charge and nothing proprietary about the fit.
How fast can I get the Irwin 66716 delivered?
Most orders ship the same day from our distribution partners, with quick delivery throughout the continental U.S. Need it urgently? Contact Us for expedited shipping options.
Can I return it if it doesn’t work for me?
Yes—ZenSupply offers a hassle-free return policy. If the product isn’t the right fit, reach out to our support team for a return authorization or setup a return by following our return instructions.
Does the Irwin 66716 come with a warranty?
Absolutely. The Irwin 66716 is backed by a manufacturer’s warranty. For full warranty terms, check the product documentation or Contact Us.
How do I get technical support or installation help for the Irwin 66716?
You can call, text, or email our expert support team for fast answers. We’re here to help with product selection, installation tips, and troubleshooting. Contact Us
Why buy the Irwin 66716 from ZenSupply?
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