8 Best Step Drill Bit Sets (Unibits) to Get in 2021

Best Step Drill Bits and Unibits (Reviews & Buyer's Guide)

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If you tend to drill holes of different sizes into thin pieces of wood or metal, step drill bits can be an indispensable tool. However, with dozens of different models to choose from, it can get difficult to know the right set to go with. In this article, I’ll help you make that choice.

While I recommend reading the whole article to find the step drill bit set that best suits your needs, I have to mention here that the Milwaukee 48-89-9223 is my favorite. It offers excellent quality, comes in a nice plastic case, and spans a wide range of sizes that will cover the needs of most projects.


HW Top Pick
Best Step Drill Bit Set

Milwaukee 48-89-9223 Step Bit 4-Piece Set

A four-piece step drill bit set manufactured by one of the most popular brands that includes sizes #1, #4, #7, #12. Works well with both wood and metal.

The Milwaukee 4-piece step drill bit set is a solid recommendation due to its high quality, durable and well-performing bits. The manufacturer even goes as far as to claim that these step drill bits are designed for 2-times faster drilling and up to 4 times longer life than the competition. Thanks to their superior performance, up to 50% more holes per battery charge can be drilled with this set as well.

These bits are ideal for drilling in steel, plastic, and wood – as such, you will find them helpful for a wide variety of projects. Each bit has a black oxide coating which both helps with drilling performance as well as lifespan.

Users will also appreciate the laser-engraved reference marks on each bit that can be easily seen while drilling for added accuracy. The 3-flat shank will ensure a solid grip within a drill chuck and jam-free performance while drilling.

Things I Like About This Product: The RapidStrike bit tips allow for fast, accurate starts and generate less heat while the dual-flute design delivers greater speed and control. This product is made in the USA. The bits come in a handy plastic carrying case.

Things to Keep in Mind Before Buying This Product: There’s not much to be faulted in this set of drill bits, thanks to the high-quality construction and durability. However, they are fairly expensive.


Best Unibit Set

Irwin 10225 General Purpose Step Drill Bit Set

A set of four single-flute step drill bits including sizes #1, #2, #4, and #21. The bits are made of high-speed steel.

The Irwin general purpose step drill bits are designed for maximum drill control and have SpeedPoint tips for fast starts. The bits are made from high-speed steel coated with titanium nitride that resists heat and friction 6 times better than other step drill bits.

These step drill bits create clean, precise holes in a variety of materials, including mild steel, acrylic, laminate and more. The set includes #1, 2, 4, and 21 size step drills.

Things I Like About This Product: The flutes have laser-etched sizes that are easy to identify while drilling to prevent over-drilling. The company stands by its products and offers a lifetime warranty against defects in workmanship and materials under normal wear and tear. These bits might not be cheap, but the quality is as expected from Irwin and these bits will last a long time with a bit of care.

Things to Keep in Mind Before Buying This Product: Remember that the largest bit size will require a 1/2-inch chuck adapter. Some reviewers have wished for a pointed end on the largest bit, but the majority of reviewers liked the product and think it provides good value for money.


Budget-Friendly Step Drill Bits

DeWalt DWA1790IR Step Drill Bit Set

A set of three titanium double-flute step drill bits covering sizes between 1/8-inch and 7/8-inch. Equipped with a split point tip and a hex shank for impact driver usage.

If you are looking for an affordable but quality set of step drill bits, you should definitely consider the DeWalt DWA1790IR. It contains three bits that are optimized for impact driver usage, but that also perform well with regular drills.

Each bit has a titanium two flute spiral design for longer life and easier chip removal. The split point tips boost their drilling speed, and the bits have laser-engraved size markings along the sides for better visibility.

Things I Like About This Product: These bits are ideal for drilling into cans, panels, and junction boxes for electricians, for enlarging holes in ducts for HVAC applications, and for enlarging door hardware for carpenters.

Things to Keep in Mind Before Buying This Product: Unfortunately, these bits don’t come with a pouch or a case to keep them in. Also, the sizes can be a bit difficult to read as they’re not engraved deeply.


Best for Metal
Best Step Drill Bits for Steel and Metal

Milwaukee Shockwave Impact Step Drill Bit Set

While compatible with drills, this three-piece set is optimized for impact driver usage. Includes sizes #1, #4, and #9.

Milwaukee makes fine products with durable and precise workmanship, and their Shockwave step bits are no exception.

Coated with titanium aluminum nitride, these bits have a considerably longer lifespan many similar bits from the competition. The hex shank is extra durable to prevent early shank breaks, and these bits are optimized for working with even the most powerful impact drivers.

In addition, sizes are clearly laser engraved on the sides to prevent over-drilling and the rapid strike tip on each bit is designed for fast and accurate starts.

Things I Like About This Product: These bits can drill holes twice as fast and last longer than the competition. They offer about as good of performance with impact drivers as it gets.

Things to Keep in Mind Before Buying This Product: While these bits are excellent, they are also quite costly. Especially considering that there are only three in the set.


The Alternatives: Other Step Drill Bits Also Worth Considering

While I recommend getting one of the step drill bit sets mentioned above, if you did not find one you like among those, you might also want to consider the four products below.


Worth Considering

Klein Tools 59009 High-Speed Steel Step-Drill Bit

A single-flute step drill bit covering sizes between 1/4-inch and 1-3/8-inches. Self-starting thanks to its anti-skid tip.

The Klein Tools 59009 high-speed step drill bit is ideal for drilling multiple sized holes in thin sections of wood, plastic or metal. The bit is made from high-speed steel and is more durable than some of the cheap step bits out there.

It covers sizes from 1/4-inch to 1-3/8-inches. It has a single flute cutter with laser-etched hole sizes for easy reading. The split point tip is designed to prevent walking, and the tri-lobe shank gets gripped firmly by the drill chuck.

Things I Like About This Product: This drill bit is fast even when drilling holes in metal and can be resharpened easily.

Things to Keep in Mind Before Buying This Product: While this bit can stand some heavy use, it has a tendency to bind easily according to some reviews.


Worth Considering

Bosch IMSDC002 Turbo Step Drill Bit Set

A pair of double-flute high-speed steel step drill bits with hex shanks. Their design allows for speedy chip removal.

 style=Bosch Turbo step drill bits are compatible with both drills and impact drivers but optimized for impact drivers accepting hex shanks. Not only do these bits work in both high- and low-speed mode, they provide faster cutting and have two cutting edges for better drilling speed.

The bits have an innovative heat management design that extends the bit life and their balanced double flute design helps eliminate vibration.

This set includes two sizes, one drilling holes between 3/16-inch and 7/8-inch and the other between 7/8-inch and 1-1/8-inches.

Things I Like About This Product: This drill bit set is good enough for professionals who need to drill holes in sheet metal, ducts, steel, copper, brass, aluminum, plastic, vinyl siding, plasterboard, PVC, stainless steel and cast iron every now and then.

Things to Keep in Mind Before Buying This Product: Unfortunately, these bits don’t have laser engraved sizes along the side, nor does the set include a pouch or case to keep the bits in.


Worth Considering

Hyclat Five-Piece Step Drill Bit Set

Contains five titanium high-speed steel step drill bits covering fifty different hole sizes. Equipped with three-sided shanks.

The Hyclat 5-piece set is exactly what’s needed if making holes of several different sizes for a more than an affordable price tag is the goal. The bits can create holes of up to 50 different sizes between 1/8-inch and 1-3/8-inches, but without having to constantly change bits.

The bits are made from high-speed steel with a titanium coating for extra durability while the double cutting blades and X-type opening design allow for faster and smoother cutting. The three-sided shank design prevents the bit slipping in the drill chuck.

Things I Like About This Product: This drill bit set is good for drilling in stainless steel sheets, aluminum alloy, plastic material, and wood. The bits can be used for a wide variety of applications such as chamfering, burring, and enlarging holes. The bit set comes with either a case. It also comes with a 24-month warranty.

Things to Keep in Mind Before Buying This Product: The bit sizes can be quite hard to read, particularly the smaller ones, so keep that in mind. Also, the bits tend to lose their sharpness with repeated use over time as is expected from an entry-level product.


Worth Considering

Neiko 10169A Titanium Step Drill Bit Set

A set of two 1/4-inch shank bits, two 3/8-inch shank bits, and a center punch. All bits are double-flute.

The Neiko 10169A titanium coated high-speed step drill bit set contains two 3/8-inch shank step bits, two 1/4-inch shank step drill bits, and an automatic center punch. The two-flute design of the step bits clears chips faster and lets particles escape faster for a cleaner cutting movement.

The bit has a tri-flatted shank to eliminate slip in the drill chuck. Each step bit has laser-engraved sizes along the sides.

Things I Like About This Product: The center punch included in the set is spring-loaded for high impact strikes that help you mark the drilling point easily. Another positive point is that the set comes in a sturdy plastic molded case to store all the items securely. This is a decent drill bit set for use on copper, stainless steel, plastic, and wood.

Things to Keep in Mind Before Buying This Product: As with most items in this range, don’t expect very durable drill bits, and be sure to use a quality oil to decrease friction while drilling.


The Methodology: What I Considered When Picking the Products Featured Above

With so many different step drill bit sets available on the market, it can be difficult to filter through them all. If you decide to do so, however, below are some of the most important factors I recommend keeping in mind when doing your search.

Price: While generally speaking, the more expensive step drill bits tend to be of higher quality, that does not necessarily mean they are the best ones for you. For example, if you only need to use yours every now and then on wood or other relatively soft materials, you will be able to get away with a cheaper set than if you need to be using them daily on steel. If your case is the former, I recommend this DeWalt set.

Quality: If you are looking for quality bits that will last you a long time, make sure to go with one of the major brands like Milwaukee or Irwin. Not only will the bits oftentimes be better than their cheaper counterparts, but they will also come with better customer service in case something goes wrong. That said, before picking a set, make sure to read thoroughly through reviews – both positive and negative.

How to Choose a Step Drill Bit Set for You

Material: Drill bits are usually made out of high-speed steel. In some cases, however, the high-speed steel is either coated or mixed with other materials for superior performance. The common versions include black oxide-coated bits, titanium bits, and cobalt bits. While all of those will work well-enough with wood, if you are planning to drill into metal, get titanium or cobalt bits like the Milwaukee Shockwave if possible.

Size: Step drill bits are a convenient tool because of their multiple-sizes-in-one-bit design. Even with that, however, the range of sizes that is covered within different sets can vary considerably. As such, before picking one, make sure it includes all the sizes you will need. That is usually the case with four-piece sets like the Milwaukee 48-89-9223.

Design: While step drill bits might all look the same at first glance, there are some differences between them. Some are able to start drilling from scratch (self-starting bits) and others – especially larger ones – require a hole to already (hole-enlarging bits) exist. Some have single flute design while others have a double flute design which clears chips faster for better and cleaner performance.

Storage: Last but not least, if possible, you should opt for a set that comes with a case, ideally a plastic one. While you can always get one separately, you will save yourself some time by not having to do so. Having your bits in a nice plastic case like the top pick comes in will also make it easier to store your bits in toolboxes without exposing them to potential damage.


The FAQs: Other Things You Need to Know

If you are unsure whether a step drill bit is what you actually need for your job – or if there is a question you have about this type of drill bit – chances are you will find your answer below.

What is a step drill bit and what is it useful for?

Just as its name suggests, a step drill bit looks like steps. That’s because it offers a variety of sizes ranging from the smallest at the top to the largest at the bottom in one piece. These bits are also sometimes called Unibits after a same-name line of step drill bits produced by Irwin Tools.

Step drill bits can be used for a variety of purposes including drilling new holes and enlarging existing holes. For the former, you will need a self-starting step drill bit. Because of their design, however, they cannot drill deep holes.

Instead, they are commonly used with relatively thin pieces of metal or wood. One common use would be enlarging a hole in a sheet of metal to fit a larger bolt.

For more about the uses of a step drill bit, read this article.

What is a step drill bit used for?

What materials can I use a step drill bit with?

While step drill bits are used commonly with sheet metal, there really is no limitation in terms of materials that they can be used with. At least when it comes to materials that are commonly used with regular drill bits.

As such, you will not have trouble drilling into metal and steel, wood, and plastic among other materials using your step drill bit. However, as mentioned in the previous question, the bigger limitation is the thickness of the material.

Can I sharpen a step drill bit?

Like other drill bits, with repeated use, step drill bits get dull and their performance deteriorates.

However, just like with most other types of bits, the performance of step drill bits can be restored through sharpening. That is most commonly done using a bench grinder.



Step drill bits – or Unibits as Irwin Tools likes to call them – are not what most people think of when they think of drill bits. However, in many applications, they are extremely useful and versatile tools to have in your arsenal.

Most commonly, you will find them useful if you work a lot with relatively thin pieces of metals or other materials. In that case, they will allow you to drill holes of varying sizes without having to change your drill bit.

They will also easily allow you to enlarge existing holes – if a bolt you are trying to install is too large for the hole, for example.

If you found yourself in one of the situations above or need a step drill bit for some other reason, I recommend starting your search with the Milwaukee 48-89-9223 and the Irwin Unibit Four-Piece Set. Alternatively, if you are on the budget, check out this DeWalt set.