Choosing the Best Step Drill Bit (unibit) Set for Metal

In my accessory box, I have several step bits, mostly Irwin and Neiko. They are best step drill bits (unibits) for metal, and give me several conveniences to increase my productivity as an electrician:

  • help make clean holes with short tool length and easier maneuverability;
  • allows me to drill faster with no need for multiple twist drill bit sizes they are incredibly useful for one-step drilling operations;
  • unibits are exceptionally well for working with sheet metal;
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Best Step Drill Bit
Neiko 10193A Titanium best unibits, High Speed Steel 3-Piece Set | Total 28 Sizes

Total 28 SizesBit #1 (6 steps): 3/16″, 1/4″, 5/16″, 3/8″, 7/16″, 1/2″; Bit #2 (13 steps): 1/8″, 5/32″, 3/16″, 7/32″, 1/4″, 9/32″, 5/16″, 11/32″, 3/8″, 13/32″, 7/16″, 15/32″, 1/2″; Bit #3 (9 steps): 1/4″, 5/16″, 3/8″, 7/16″, 1/2″, 9/16″, 5/8″, 11/16″, 3/4″

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These Neiko bits are made of HSS with Titanium coating, and have 135° split point tip. They are the best unibits for drilling holes in plastic, aluminum, copper, stainless steel and many other types of sheet metal.

Titanium coating helps to reduce overheating of the cutting edge. Two-flute design clears chips faster, three-flatted shank fits into power tools chuck more securely and eliminates slip.

Neikos are not the best unibit for stainless and hardened steel (better use cobalt bit), but for plastic, wood and thin metal sheets they are perfect. And I don’t recommend starting a new hole with these bits, except maybe in a very soft material.


If you make an occasional modification of some boxes or other products made of soft sheet metal, they are more than enough.

1/2″ bit is long and has small steps, so it can peel material in thin layers. The 3/4″ has larger ‘steps’ so it has a difficulty of engaging thick material.

Bits work wonderfully. Just remember: with metal, go slow and use cutting oil. The case they came in is ready to be abused in your tool bag but will certainly keep it safe.

If you really need to drill thick stainless with HSS+titanium Neiko bit, you can do it.

– Use cutting fluid or at least WD-40 on the bit and on the hole, including the inside of it once you’ll open it up.
– Set your drill or drill press on low speed, high torque.
– Make a starter hole with a center punch
– Drill a pilot hole (something about 1/8″)
– Start drilling at a slow speed, applying a fair bit of pressure. The bit should be constantly cutting into the metal, no dumb spinning and smoking, or you’ll wear out the cutting edge.
– If it starts smoking, stop, add the fluid or WD-40 and let it cool.
–  Stop and let the bit cool st each step, then add the fluid before starting again.
– At the end, use high speed to smooth the edges.

As a result, you can drill many holes without dulling.


best step drill bit for metal
Neiko 10197A Titanium Best Unibit Set, High Speed Steel 5-Piece Set | Total 50 Sizes

Drill Bit #1 (10 step sizes): 1/4″, 3/8″, 1/2″, 5/8″, 3/4″, 7/8″, 1″, 1-1/8″, 1-1/4″, 1-3/8″; Drill Bit #2 (12 step sizes): 3/16″, 1/4″, 5/16″, 3/8″, 7/16″, 1/2″, 9/16″, 5/8″, 11/16″, 3/4″, 13/16″, 7/8; Drill Bit #3 (9 steps): 1/4″, 5/16″, 3/8″, 7/16″, 1/2″, 9/16″, 5/8″, 11/16″, 3/4″; Drill Bit #4 (13 steps): 1/8″, 5/32″, 3/16″, 7/32″, 1/4″, 9/32″, 5/16″, 11/32″, 3/8″, 13/32″, 7/16″, 15/32″, 1/2″; Drill Bit #5 (6 steps): 3/16″, 1/4″, 5/16″, 3/8″, 7/16″, 1/2″

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best step drill bits for steel
Neiko 10189A Step Drill Bit | 12-Step Bit with Titanium Coat

7/16″, 1/2″, 9/16, 5/8″, 11/16″, 3/4″,
13/16″, 7/8″, 15/16″, 1″, 1-1/16″, 1-1/8″

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Best Unibit - Irwin 10234CB
Irwin Industrial Tools 10234CB 4 Best Unibit 3/16- Inch – 7/8-Inch, 12-Steps Cobalt (1/16- Inch Steps)

From 3/16″ to 7/8″ in increments of 1/16″

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The unibit made of M35 grade Cobalt HSS, designed with a radial concave flute, 3-Flatted shank, and SpeedPoint tip.

It is the best unibit for drilling precise round holes with a smooth, clean finish in a variety of tough materials like stainless steel, sheet metal, aluminum, fiberglass, plastics, plexiglass, and wood.

The cobalt high-speed steel provides increased life for tough applications and the SpeedPoint tip penetrates fast and doesn’t require a pilot/starting hole.

Permanent laser-etched sizes inside flute are easy to read for precise control during the hole enlarging process.

A little pricey at about 30USD but worth something that doesn’t slip and goes through like butter. Excellent craftsmanship and not a flaw in the design.

best step drill bit set
Milwaukee 48-89-9224 6-Piece Set (1, #4, #6, #7, #8, #9)

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Milwaukee bits have black oxide coating. They are dual-flute and have laser-engraved reference marks. They are the best unibits optimized for cordless drills made in the USA.

These tools are pretty good and for DIY projects it never seemed to dull down. 1/2″ Milwaukee hole shooter is the most powerful for it’s size.

ABN Titanium Step Drill Bit - 10 Steps
Titanium Step Drill Bit – 10 Steps from 1/4″-1-3/8″ Inches for Plastic, Wood, Metal – Steel, Brass, Aluminum, Copper

Sizes include: 1/4″, 3/8″, 1/2″, 5/8″, 3/4″,
7/8″, 1″, 1-1/8″, 1-1/4″, 1-3/8″

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Best unibit for mild materials: steel, brass, aluminum, copper.  It is coated in Ti and made in two-fluted design, super cheap and works fine in mild steel.

It is a decent bit and it works. If you want to get the start perfect then use the unibit to go to the size of the threads on the knockout punch and you won’t have to use the hash marks on the punch to center it.

My “front line” unibits are Irwin, but I have been starting to buy cheap ones to keep “in stock”. They cut not so bad, last not so long as the brands, but they are cheap enough to toss when they start losing their edge.

best step bit set
ABN 3-Piece – best unibit set made of M2 Steel – 28 Sizes, SAE

13-Step Bit: 1/8″, 5/32″, 3/16″, 7/32″, 1/4″, 9/32″, 5/16″, 11/32″, 3/8″, 13/32″, 7/32″, 1/4″, 9/32″, 5/16″, 11/32″, 3/8″, 13/32″, 7/16″, 15/32″, 1/2″- 3/16″ to 1/2″ 6-Step Bit: 3/16″, 1/4″, 5/16″, 3/8″, 7/16″, 1/2″- 1/4″ to 3/4″ 9-Step Bit: 1/4″, 5/16″, 3/8″, 7/16″, 1/2″, 9/16″, 5/8″, 11/16″, 3/4″

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It is a M2 bits set. Bits are Ti coated and have two-flute design.

For the price It is really the best unibit – little and cheap kit.

The case is very nice and a handy place to keep them, great set to have in tool box.

I used a the bit punch clearance holes for 1/2″ and 3.4″ conduit through hardened steel girts on my metal building. I used cutting oil and ran it with a Milwaukee 1/2″ variable speed drill at pretty slow speeds. I drilled over 100 holes with that bit and it still works!

The steel was so hard that I quit trying to use knockout punches on it after about eight holes, and the plumber stripped the threads on a punch after two holes. I believe, on mild steel boxes, it should last even longer if not run too fast.

Capri Tools ST-243 Titanium Step Drill Bit
CO-Z Titanium Step Drill Bit

Step sizes: 1/4, 3/8, 1/2, 5/8, 3/4, 7/8,
1, 1-1/8, 1-1/4, 1-3/8-inch

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Capri tools are the best unibits among low-priced. They have 3/8-inch shank with 3 slip-resistant flat sides, double flute for convenience, self-starting.

For steel, copper, stainless steel, plastic, aluminum, and other thin materials.

It is best unibit in low-cost segment, but it does not word good for stainless steel. Steel – only thin sheets. In other soft materials it delivers a clean hole without burrs.

And about “self-starting”, you NEED a center punch one, at least on steel. The numbers rub off quickly.

I sometimes sharpen cheap unibits. If it’s a true Unibit, the flute is cut with a radiused milling cutter on a chordal path to provide a back rake angle to the cutting edge. To sharpen it, I dress a 1/4″ or 3/8″ wide type 1 grinding wheel to a radius roughly equal to that of the flute. Holding the bit to the wheel, grind the radius to undercut the flute face on the cutting edge side. Keep grinding lightly until the tool sharpens up, being careful to maintain the positive back rake of the flute. It should only require a few quick applications to the wheel to bring it back unless it’s totally trashed.

For many other brands, such as Milwaukee, use a type 1 wheel dressed to a wedge face or a type 11 or 12 cup wheel. Grind away a little bit of the cutting edge face until it sharpens up.

The true Unibits with radiused flutes can be sharpened a substantial number of times if you keep them sharp so the corners don’t break down. The other types can be sharpened a few times, but they’re a much cheaper design and don’t have a lot of extra metal to allow for sharpening

Hitecera 5-Piece 10197A Metric Step Drill Set
Hitecera 5-Piece 10197A Metric Step Drill Set HSS Cobalt Multiple Hole 50 Sizes 1/4-Inch and 3/8-Inch Shanks, SAE, w/Aluminum Case

50 Sizes 1/4-Inch and 3/8-Inch Shanks, SAE, w/Aluminum Case

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Five standard with a two-flute design.
A complete SAE set: Two popular 1/4″ and 3/8″ shank sizes to cover a wide range of drilling requirements.Includes aluminum carrying case.
Best step drill bit set among low-price tools. Cobalt coated to reduce friction and run cooler. A Large bit has a 3-sided shank and small bits have hex shank to prevent slip in a drill chuck. The set is less expensive than a single bit from other retailers. Cobalt coated is not cobalt steel. M2 is most widely used industrial molybdenum HSS, usually used to manufacture a variety of tools.
Bits come very nicely packed in little carrying case embedded in foam.The quality is quite good, M2 HSS steel durable enough and allows you to work even on stainless steel IF you will choose proper pressure and speed and use lubrication.
For the price, buying the set is a no brainer.

I’m using my best unibits at work to drill holes (7/8″) in electrical boxes. I love them and I have always used these little monsters. Personally I using an Irwin, you may use any reviewed, but my best unibit is Irwin. I have 2 piece set from HD and the 3 piece HF set on sale at the recommendation of a guy at work. Both are nice & go through thin sheet without issue. Haven’t used them for anything else.

Best Unibit (Step Drill Bit) Review
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Best Unibit (Step Drill Bit) Review
Unibit or step drill bit provides several benefits: - helps to make clean holes with short tool length and easier maneuverability; - provides faster drilling, no need for multiple usual twist drill bit sizes; - work exceptionally well on sheet metal; - incredibly useful for one-step drilling operations. We spent a lot of time to find step drill bits that works fine and doesn't cost an arm and a leg. Read our review to choose the best unibit for your project.
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16 thoughts on “Choosing the Best Step Drill Bit (unibit) Set for Metal”

  1. Needed a bit to install a large temp gauge for a Weber grill. Went to home depot and they wanted 50 bucks for a Milwaukee step drill bit. I’m sure it’s nice but i decided to wait for 2 day shipping and save 40 bucks. I’m glad I did this pushed through the metal quickly with a clean finish. I couldn’t be happier.

  2. My favorite is Neiko one.
    It is one of those tools that once you own it, myriad applications previously not considered magically appear.
    It is a tremendous cost saver when compared to purchasing individual bits of equivalent diameters. Yet, it has a few advantages over conventional bits as it acts as a nice deburring tool in certain circumstances. It can also be a great time saver when installing electrical connectors and switches in electronic enclosures or automobile dashboards. You don’t have to constantly switch bits.

  3. Saw a titanium step drill bit on ebay for 900 dollars. ABN set can easily go for 50 bucks, so this was a good price and works great. For the inexperienced, use oil! I won’t let anyone use this at work unless they use oil. I’ve made cheat drill bits last over 250 holes because I use oil! If you don’t it heats up the metal – hardening the metal and making it harder to drill and wears out your bit!

  4. My unibits are by ABN.
    I was very skeptical when I purchased this item. Most of the negative reviews were about smoking issues, which I assumed (and now believe) were due to user error. I was pleasantly surprised with this item.

    I needed to drill four holes in sheet metal. 1 hole at 1 1/4 inches diameter thru 16 guage (1/16 inch) thick sheet metal and 3 holes at 1 3/8 inches in diameter thru # 3 guage (1/4 inch) thick sheet metal. Each hole took about five minutes and was more smooth than I expected, especially when I opted to use a hand drill.

    Here are some tips for success.

    *Once you mark the center of your hole, use a punch to create a dent in the metal. This will help you drill the starter hole.

    *If you have a regular set of drill bits, use the largest available (under the size of the desired finished hole the step bit will cut). This will be faster and cause less wear to the step bit.

    *Use plenty of cutting oil, 3 in 1 oil or in a worst case, cooking oilI. Oil both the bit and the work. (Please don’t dislike my review because I mention cooking oil, its not the best option, but it is better than trying to cut the hole dry.) Drilling dry will cause smoke and destroy the bit.

    *while you are drilling, say every step or two (depending on the thickness of the metal), whipe away the metal shavings and reoil both the work and the bit.

    *Drill slowly. If the bit starts to smoke, you are either going too fast, pressing to hard, and / or dont have enough oil.

    *Once you are thru the work at the desired step (size), turn the work over and drill lightly from the back side. This will clean up and jagged pieces of metal and give it a professional look.

    *Be very careful, use goggles or a face shield and leather gloves. Especially if you are a new DIYer.

  5. My favorite is Neiko 10194A titanium unibit.

    For the price, I like its solid, heavy quality right out of the box. I purchased this exclusively for drilling an 11/16″ hole in a stainless steel sink to install a water filter faucet. I didn’t have a single drill bit this large so I figured this would be more functional for any future projects. This thing chewed right through! I had to drill a pilot hole with a 1/8″ bit to keep it from walking. I also used a few drops of oil each time I started back up to keep it cutting. My basic 9.6v drill had to be recharged some to get the job done, but I’m sure a decent drill or corded drill would have had this done in a matter of seconds.

  6. I don’t have much experience with step bits so I don’t know how it compares to other brands. I’m drilling aluminum, so my Makita unibit cut through very easily, but left a very rough hole. The same for some stainless I drilled. Cuts fine but rough hole that requires some filing and deburring.

  7. I’ve bought DEWALT DWA1789IR This is awesome! I’ve used this for drilling 2 different metal panels, more than 20 holes. Also had to drill underground meter ped for relocating pipe. The unibit makes holes very fast and smooth. Best step bit I’ve owned. A must have for any electrician!

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