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Irwin Tools Unibit #9 7/8-Inch and 1-1/8-Inch Step-Drill Bit, 1/2-Inch Shank (10239)

4.5 out of 5 stars 122 customer reviews
| 6 answered questions
List Price: $92.05
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High Speed Steel
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  • Imported
  • Single-flute cutting edge for greater control through steps
  • SpeedPoint tip penetrates fast and helps prevent walking
  • Hex shank helps prevent slipping in the drill chuck
  • IRWIN Unibit step drill bits are ideal for drilling holes into thin materials, such as stainless-steel, copper, brass, aluminum, plastic and laminates
  • Drills 7/8-inch and 1-1/8-inch holes
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Frequently Bought Together

  • Irwin Tools Unibit #9 7/8-Inch and 1-1/8-Inch Step-Drill Bit, 1/2-Inch Shank (10239)
  • +
  • Irwin Tools Unibit #3 1/4-Inch to 3/4-Inch Step-Drill Bit, 3/8-Inch Shank (10233)
  • +
  • IRWIN Unibit High-Speed Steel Fractional Self-Starting Step-Drill #5, 10235
Total price: $74.28
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WARNING:
CHOKING HAZARD -- Small parts. Not for children under 3 yrs.

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This item Irwin Tools Unibit #9 7/8-Inch and 1-1/8-Inch Step-Drill Bit, 1/2-Inch Shank (10239)
Customer Rating 4 out of 5 stars (122) 4 out of 5 stars (31) 5 out of 5 stars (8) 4 out of 5 stars (135)
Price $27.62 $22.12 $19.99 $9.80
Shipping FREE Shipping $4.74 FREE Shipping FREE Shipping
Sold By Amazon.com cargolargo Drill Hog Amazon.com
Material Type High Speed Steel Stainless Steel Hi-Molybdenum M7 HSS Steel, Cobalt M42, Titanium, HSS, High Speed Steel M2 Titanium
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Product Description

Size:#9 (7/8" + 1-1/8")  |  Style:High Speed Steel

Product Description

This IRWIN Unibit #9 High-Speed Steel Fractional Self-Starting Step Drill Bit features a single-flute cutting edge for greater control through each of its 2 steps. The sharp SpeedPoint tip penetrates fast and helps prevent walking, while the hex shank helps prevent slipping in a drill chuck. Use this reliable drill bit to drill holes into thin materials like stainless-steel, copper and more.

From the Manufacturer

UNIBIT 9 2 Hole Sizes (7/8" and 1-1/8" )for 1/2" and 3/4" KO

Product Information

Size:#9 (7/8" + 1-1/8")  |  Style:High Speed Steel

Technical Details

Additional Information

Warranty & Support

Warranty, Parts:Parts
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Customer Reviews

Top Customer Reviews

4.0 out of 5 starsGreat for it's designed purpose..
By A Customer on June 25, 2000
Style Name: High Speed SteelSize: #4 (3/16-7/8")
The unibit is fantastic for putting holes in thinner material. A plus is the hole will be deburred on the side you are drilling from. When drilling stainless steel (my experience was with 1/8" 316 ss) be careful to reduce RPM as each step goes through. It can work harden the material easily, and ruin the bit. A definate "MUST HAVE" for working with electrical enclosures and panels as well as sheet metal. Just don't throw away your normal twist drills.
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5.0 out of 5 starsHigh Quality Bit, Works well in Plastic, Metal, Wood
By Joe Mooney VINE VOICE on January 24, 2015
Style Name: High Speed SteelSize: #2 (3/16-1/2")
This Irwin 10232 Unibit is a high quality set step drill, made in the USA. While it does cost more than competing off-shore bits it is also significantly superior in all respects.

The Good:
Smooth, sharp cutting edges allows one to produce clean accurate holes with ease in thin metal, plastic and wood.
Pointed tip does indeed prevent the bit from wandering or skipping when starting a hole. No counterpunch or pre-drilling required to achieve accuracy.
The shank is formed to fit 1/4” hex drivers. The amazon product photo does not show these newer driver style shanks (at the time of this review).
Markings are highly visible and easy to read.
The quality workmanship of this product is obvious: sharp, finely machined, highly visible markings.

The Bad:
There really isn’t anything serious to complain about, so consider the following list to be nit-picking…
The bit fits standard 1/4” hex drivers, but the shank section before the groove is a bit shorter than normal (see photo). This is no problem whatsoever in magnetic drivers. In my non-magnetic Makita impact driver the bit had slightly more in-and-out play than usual, but it did not affect drilling performance. (I warned you I was nit-picking!).

Summary:
If you enjoy using top quality tools then this set is worthy of your consideration.

If you like short reviews - stop here!

On the other hand, if you like lots of extra information, then please by all means read-on…

The bit has a hex shank for positive slip-free use in standard drill chucks. This #2 bit also fits in standard 1/4” drill drivers, impact drivers, etc.Read more ›
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5.0 out of 5 starsDrilling guitar endpin jack holes.
By Allan on June 7, 2015
Style Name: CobaltSize: #1 (1/8-1/2") Verified Purchase
I bought this bit as part of my tool kit to drill endpin jack holes in expensive guitars to mount the endpin jacks for internal pickups. Any drill bit will make a hole, but I wanted to make sure the wood on the guitars would be in perfect condition after the hole was drilled. Causing serious damage to a $5,000 guitar can ruin a guy's day, especially if he's the owner of the guitar. Typically, if no prior hole exists, a new 1/4" hole is drilled with a sharp brad point drill bit, followed by a precision tapered reamer from a guitar luthier supply house. However, sometimes a smaller hole already exists where a strap button was screwed in or a tapered end pin was press fit into a tapered hole. Perhaps the tapered endpin was even glued into the tapered hole and can't be removed without drilling. If a strap button had been screwed in, then the screw hole could be filled and a new hole could be drilled as if none had ever existed, followed by the precision reamer to safely bring the hole to its final dimension. On the other hand, this Irwin Unibit could be used to drill a tapered hole, using the strap button screw hole as a pilot hole, followed by the precision reamer to bring the hole to its final dimension. I have used the Unibit for this exact purpose, and it worked beautifully, with no damage to the guitar. If a tapered wooden strap button has been glued in, the button can be carefully sawed off near its base, and the hole can be drilled with a brad point bit and then reamed, just like the situation where no hole ever existed. But no sawing is needed if a punch is used in the center of the wooden end pin, a 1/8" pilot hole is drilled with a normal twist metal bit or a brad point bit, and the the Unibit is used to drill through the strap button and into the guitar.Read more ›
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5.0 out of 5 starsGreat example of Irwin quality in machine tools.
By B. Tsai on July 15, 2012
Style Name: CobaltSize: #4 (3/16-7/8") Verified Purchase
Anyone familiar with the Irwin name knows that they are producers of high quality machine tools. Be careful, like a lot of companies, some Irwin products are made offshore.

When this bit arrived I put it to use immediately. I had previously been using a set of old Harbor Freight step bits, back when they actually made a reasonably industrial product. These bits lasted years until the TiNi coating wore off. I recently moved to harder steel grades and had to use cobalt bits for certain production runs.

Even with slotted holes that would normally destroy a stepped drill bit as a result of chipping, this bit held up just fine and still cuts mild steel like it was made of butter. I would not hesitate to buy another one of these bits in other shapes. I can probably expect this bit to last several more years.

I only wish that the bit was a twin fluted design for better chip clearing, but no complaints yet.
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5.0 out of 5 starsDrilling through 1/2 steel
By J on August 26, 2013
Style Name: CobaltSize: #4 (3/16-7/8") Verified Purchase
This bit is unstoppable. Used in a steel fabrication project that required drilling dozens of holes in 1/2" and 3/8" steel and this bit chewed through whatever I put in front of it. Using a 1/2" variable speed corded drill and cutting oil, I was able to drill a 7/8" hole in 1/2" mild structural steel in under 2 minutes, start to finish. This bit also lasted through a dozen holes and was just as sharp at the end as when I started. The cobalt steel is worth the extra $$. This is also a GREAT price!

Things to keep in mind:
Keep the drill and bit cool and well greased.
Go SLOW!! High speed will burn this bit up in no time. Use adequate pressure, and keep the RPM's low.
Invest in a good cutting oil.
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Most Recent Customer Reviews

5.0 out of 5 starsAlways happy with irwin step bits.

I love irwin step bits and this one wasn't an exception. Took out nice soft copper very easily. with no real signs of wear after going through about 1/4 of copper.

Published 1 month ago by EN Wags
5.0 out of 5 starsFive Stars

Very good, fulfills what he promises

Published 1 month ago by Amazon Customer
5.0 out of 5 starsvery good tool

Contains all common size I need and the cutting edge is sharp. I bought this to make a hole for gasoline can vent cap. The bit was very aggressive through the plastic.

Published 3 months ago by ventingisok
5.0 out of 5 starsFive Stars

Great Product!

Published 3 months ago by Allison
3.0 out of 5 starsDue to the single cutting edge this is a very ...

Due to the single cutting edge this is a very slow bit. If you are interested in speed during your working hours, buy the bits that are $15.00 more with the two cutting edges.

Published 3 months ago by Christopher
4.0 out of 5 starsFour Stars

Irwin makes acceptable tools.

Published 3 months ago by Endeavor to perservere
5.0 out of 5 starsFive Stars

It was just as described

Published 5 months ago by Paul Peterson
3.0 out of 5 starsThree Stars

Had to send it back because it could not fit my drill as it was way to large.

Published 5 months ago by sursattie
5.0 out of 5 starsEven if this one lasts the same still a great buy.

I wore a non coated one out after ten years of hard use. Even if this one lasts the same still a great buy.

Published 6 months ago by Dana R. Longever
5.0 out of 5 starsFive Stars

A versatile drill bit due to it's multiple measurings

Published 7 months ago by Luis J.

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