Best Drill Bit For Hardened Steel Bolt – Buy in 2021

When you visit a market to buy the best drill bit for hardened steel bolt, you are often feeling confused because plenty of brands are serving in the market.

best drill bit for hardened steel

Your job to select one brand becomes difficult. So we are going to review some best drill bit sets for the knowledge of our readers.

Features to consider in the best drill bits for hardened steel bolts

Bolts that are designed with the hardened steel are really the durable ones. And one thing is clear for sure that you cannot use every type of bit with it. Here we discuss the features of the drill bits for the hardened steel bolts one by one.


This is the most important feature of the drill bits that are considered for the hardened steel bolts. This is so because bits having durable and strong material will be only worth working with the hardened steel bolts.

Carbide, Cobalt and High Speed steel are the three main materials and they are preferred while choosing the bits for hardened steel bolts. Cobalt is generally a first preference as bits made of this material are more versatile.

High speed steel is the cheaper option but still good for drill bits. On the other hand, there is the drill bits made of Carbide. They can be used with any type of steel and ideal ones for hardened steel bolts.


Another important feature that plays a vital role in the selection of the best drill bits for hardened steel bolts is the coating. Coating is a layer above the drill bits that make them more durable and they can withstand wear and tear easily.

For hardened steel bolts, drill bits that feature black oxide or TiCN coating are always good as they make bits long lasting by providing them great resistance.

Flute Design

Drill bits feature a particular flute design. Flute design refers to the design that helps to keep the waste material away while working. Probably there are two flute designs. One is the parabolic design and second one is the 30 degree angle design.

Well parabolic is only good for the soft materials and if you are working the hard materials like hardened steel bolts then 30 degree angle flute design is the right choice.

Length and angel of drill point

This feature also makes a sense for users. It is important to consider the length of drill bits. Drill bits are selected keeping in view the material that you have to work with. In case of hardened steel bolts, you need small drill bits because they are so rigid and they eliminate the chances of breakage during work.

Always pay attention to the angle of drill bits. Angle selection is mandatory for the precision and efficiency in the work.


Although this feature is not mandatory and it has nothing to do with the working but it is good if the feature of portability of drill bits is high. It is high when the bits come in a carrying case and they can be easily stored at a small place to carry them anywhere.


Versatility of drill bits is the feature that is important to consider because versatile drill bits can be used with other projects in addition to the working with hardened steel bolts.

Best Drill Bit For Hardened Steel Bolt Review

1. Bosch CO14B 14 Pc. Cobalt M42 Drill Bit Set

This Cobalt M42 drill bit set that offers more enhanced and powerful M42 cobalt jobber bits which are specifically designed for stubborn surfaces of cast iron, stainless steel, aluminum, titanium and it is also good for the light gauge metal. This drill bit set is durable and provides excellent resistance against high heat.

Cobalt M42 Drill Bit Set

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It can fight against heated applications for longer intervals. These hard-line cobalt bits distribute 10X life in comparison to the other standard one bit.

Its Thick Web-Helix design helps in the fast removal of materials and delivers amplified solidity. Bits are 1/8 in size and another feature that cannot be ignored is a split point that is 3/ 16 in.

Its dimensions are 9 x 4.6 x 1.6 inches. If you are concerned about its weight, it is a lightweight product with 1.06 pounds. No batteries are required to run this drill bit set. For a better bit grip, a unique feature is included that is a three-flat shank.

It has a fast and appropriate start-up function which decreases the bit walking on different material facades. It includes a strong surface tip which can easily move into the deeper corners or surfaces.


  • Cobalt drill bits are better than other bits in terms of cutting; they can incise any harder material fastly. Usually, 1 bit is required to make 16 holes through a 1/ 8 metal bed rails. On the other hand, a regular bit would not be able to meet this requirement.
  • The complete bit is composed of M 42 8 % cobalt alloy that’s why it will last for longer but it is a little bit expensive too.


  • These drill bits will not cut through a file but they can just drill it.

2. Drill America 115 Piece Heavy Duty KFD Series

These are the specifically produced drill bit set and its diameter is 1-60 inches. Its weight is 4.00 pounds. This drill bit set includes 115 bits in a metal case. It can be utilized for a variety of materials like steel, iron, aluminum, stainless steel and many more hard materials.

Drill America 115 Piece

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This package offers a 135-degree tip that features a split bit and it helps to minimize thrust and self-centering. As compared to 118 degree traditional tip, these bits will never betray you. These are available in gold and black surface that can be used for drilling in hard materials and stainless steel.

These drill bits are available in different sizes. Its standard size is 1/16″- 1-1/2″, A – Z, #1 – #52 and 1mm – 13mm.It also offers 1/2” or 3/8” Reduced Shank or it has an amazing feature that is quick change hex shank. Its dimensions are 6 x 4 x 2 inches.


  • This drill bit set is considered one of the best industrial cutting tools.
  • Every drill bit size is available in this package that you have ever imagined.
  • These drill bits provide excellent efficiency and performance and can be used for several times without any hindrance.
  • This is a perfect light drill bit set with an economical price.
  • Just keep one thing in your mind, exercise them at a suitable speed, make proper use of cutting oil and never overheat the drill bits, if you follow all these rules, it will enhance their life and they can stay for long.


  • The box which contains these drill bits is cheap and poor, it does not look like that hout box as mentioned, as a result of its poor packaging, the drill bits inside might be scattered.

3. High-Speed Steel Drill Bit for Professional Duty

This package’s dimensions are 8 x 5.3 x 1.6 inches. Its size is 3/8; 5/16; 1/4; 3/16; 5/32; 1/8; 5/64. It is available in gold color. This fast pace drill bit set is specifically designed in Europe which is composed of high-quality M2 steel which is shaped in France, Germany and Austria.

High Speed Steel Drill Bit

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This drill bit set is a perfect choice for professionals, constructional steel, iron, metals, alloys and other plastic materials; furthermore, it can also be utilized for industrial use.

It includes an exclusively intended split point which is best for easy drilling and also offers excellent performance. It provides an exact hardness score that is (62, 5, 63, and 5).

If the score is lower, it results in lower stiffness, on the other hand, a high score result creates a weakness in a drill bit. Basically, its production line is established to meet ISO EN 9001, GOST, JIS, DIN and ANSI.

Commonly, this drill bit set consists of 7 drill bits which are cautiously chosen to meet all the construction and household requirements.

And, there is no doubt that Profi’s drill bits are the ultimate demand of top-notch companies like luxury Swiss Watches Company, German car manufacturers and premium class tires manufacturer.


  • Solid metal is used in the preparation of these drill bits, as a result, these drill bits are more long-lasting, might be filed many times and it is really hard to smash these bits into half.
  • These drill bits can be used to drill tiles and concrete, but it is not suggested to perform this job time and again, because it will reduce the toughness and performance of drill bits.


  • These drill bits are not recommended to use with dermal rotary.

4. SPKLINE M35 – 13 Pcs Cobalt Drill Bit Set

Its weight is 8 ounces. Its dimensions are 5.3 x 3.5 x 1.1 inches. Its diameter is 1.5 – 6.5mm (1/16″-1/4″).This high-speed drill bit set includes 13 pieces with most frequently used sizes for clear-cut whole drilling into a variety of materials.

Even, you can find information about its different sizes, which are 1.5mm(1/16″), 2mm(5/64″), 2.5mm(3/32″), 3mm(7/64″), 3.2mm(1/8″), 3.5mm(9/64″), 4mm(5/32″), 4.5mm(11/64″), 4.8mm(3/16″), 5mm(13/64″), 5.5mm(7/32″), 6mm(15/64″), 6.5mm(1/4″).

It is a tough yet versatile drill bit set which provides excellent efficiency regarding heavy-duty drilling.

SPKLINE 13 Pcs Cobalt Drill Bit Set M35

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It is good enough for a wide range of materials just like high-carbon steel, alloy steel, and aluminum, cast iron, abrasive alloy metal, stainless steel and many other hard metal and hardened steel.

As far as, its lifetime is concerned, it is 4 times better than the traditional metal drill bits while dealing with plastic, jewelry, sheet metal, wood, normal steel and PCB board.

Commonly, industrial-grade High-Speed Steel is used in the preparation of M35 Cobalt drill bits which also constitutes 5% cobalt alloy that works as a heat and erosion resistant.

If you want to start work immediately with less power, then you can take advantage of its 135-degree tip that contains a split-tip and which is great to reduce walking gliding beyond the work surface.

It has a straight shank that fits well with a cordless power drill, electric drill and rotary drill.


  • As far as, its packaging is concerned, these bits are wrapped in a Metal Indexed Storage case for comfortable storage and arrangement.
  • It is an ideal tool for professionals who work in metalworking workshops. On the other hand, it is also appropriate for IT hardware engineers, maintenance staff, jewelry artisans, hard metal part processors, repairing, woodworking DIYers and metalworking craftsmen and for other professionals.
  • It can reach into hard to core areas and provide better drilling service


  • Overall this a good product and it has no such con.

What things you should keep in your mind before buying drill bits?

It is very important to understand this fact that different types of drill bits are available in the market. So always choose the accurate drill bits according to your job and project. Here, we will talk about a variety of drill bits that can bring ease to your drilling tasks.

  • Brad-Point Drill Bit: This point is particularly manufactured for boring into wood. The brad located at the center of the bit tip supports the bit exactly for appropriate drilling and creates a clean outlet in the workpiece.
  • Twist Drill bit: This is the most common type of drill bit set for household tasks. It goes well with wood, plastic and other light metals.
  • Installer drill bit: The length of this drill bit can be 18 inches long and drill through masonry, wood and plaster.


In market, plenty of brands are working and their main aim is to satisfy the customer’s needs to the fullest. Same is the case with the drill bits industry. There are so many brands that offer the drill bits for the hardened steel bolts and they vary in their quality and versatility.

So it mainly depends upon the needs of the user that what he is actually looking for in a product. Remember always think wisely while making a decision about drill bits for hardened steel bolt as you invest probably once and if you do not select wisely, your investment may get wasted.


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