Drill bits are cutting tools primarily used to create cylindrical
holes. They come attached to a drill, which spins them and provides
torque and axial force to create the hole. Drill bits come in many
shapes and sizes, and the material they’re made of can vary widely
depending on the specific task they’re designed to perform. The right
drill bit can make any drilling task easier, whether it’s drilling into
wood, metal, concrete, or any other material. A high-quality drill bit
will not only make your work more efficient but can also give you clean,
precise holes, ensuring that your finished work is of high quality. It
should be noted that not all drill bits are created equally. The drill
bit used can significantly contribute to the outcome of your drilling
job, highlighting the importance of choosing the right one for your
specific task.
Importance
of choosing the right drill bit for specific materials
Choosing the right drill bit for a specific material is an essential
aspect of any drilling project. The suitability of the drill bit to the
material being drilled not only acts as a determinant of the efficacy
and efficiency of the work but also increases the longevity of both your
drill and the drill bit. The material, shape, size, and type of the bit
can greatly affect the quality of the output. If you’ve ever tried to
drill through hardened steel with an inappropriate drill bit, you’ll
know the struggle. The wrong bit may not be able to penetrate the steel,
or could wear out quickly, or even worse, it could break during the
process, risking safety. Therefore, understanding and selecting the
right drill bit for drilling through materials such as hardened steel is
instrumental to ensure smooth drilling operations and optimal
results.
Understanding Hardened Steel
Definition of hardened steel
Hardened steel is a form of steel that has undergone a process known
as hardening, which involves heating the material to a specific
temperature before rapidly cooling it. This process transforms the steel
into a much harder and more durable material. Hardened steel is commonly
used in a variety of applications due to its toughness and resistance to
wear and tear. It is aptly suited to high-stress applications like
gears, drill bits, cutting tools, and other industrial components. Due
to its high strength, it has a high resistance to deformation, dents, or
scratches, making it more challenging to work with than softer types of
steel.
Challenges in
drilling through hardened steel
Drilling through hardened steel is anything but easy, and a task
fraught with numerous challenges—the reasons are aplenty.
Firstly, the extreme hardness of the steel makes it incredibly tough
to pierce through. Standard drill bits often prove incapable of
penetrating the surface effectively and tend to become blunt or damaged.
This can lead to wastage of both time and resources.
Secondly, the intense friction caused by the drilling process
generates a lot of heat. If not properly managed, this heat can result
in damage to both the drill bit and the steel surface, causing them to
warp or even break.
Third, the task requires precision. Hardened steel is not forgiving
if a mistake is made during the drilling process. A wrong move can
result in unexpected damage to the material or shift the drilled hole
off its intended mark.
Lastly, drilling hardened steel quickly drains battery-operated
drills due to the needed power. This further complicates matters if
you’re working on a large project.
Cognizance of these challenges is important when drilling through
hardened steel, as they should influence the selection of the tools and
methods used for the task.
Factors
to Consider When Choosing Drill Bits for Hardened Steel
Material of the drill bit
The material of the drill bit plays a crucial role in deciding
whether it is suitable for drilling through hardened steel or not.
High-speed steel (HSS), solid carbide, and cobalt steel alloys are the
most commonly used materials for manufacturing drill bits designed to
work with hardened steel.
HSS drill bits are a good option for normal steel and iron. However,
when hardened steel is in the mix, they might not be the most competent.
They can become dull faster, and continuous drilling can lead to
overheating.
Solid carbide drill bits, on the other hand, are extraordinarily
hard, maintaining sharpness longer than many of their counterparts. The
downside, however, is their brittle nature. They can easily break if
they are not handled with care or if subjected to side stress.
Cobalt steel alloys are renowned for their fatigue resistance and
capacity to withstand high temperatures. As a result, they are ideal for
cutting through hardened steel that inherently generates a lot of heat
due to its density. Cobalt drill bits are tenacious and retain their
sharpness for an extended period, making them a suitable choice for
drilling through hardened steel. They might be more expensive than other
options, but their strength, durability, and excellent performance
justify the cost.
Shape of the drill tip
The shape of the drill tip is a crucial factor to consider when
shopping for drill bits for hardened steel. The two main types of drill
tip shapes are split point and twist.
Split point drills are an excellent choice for hardened steel. This
type, also referred to as self-centering drills, have an enhanced
cutting angle which provides faster cutting and requires less exerted
force. They start on contact without the need for a center punch to
prevent the drill bit from ‘wandering’.
On the other hand, twist drills, or jobber drills, are more
traditional, having a simple design that makes them versatile across
many materials. However, when it comes to hardened steel, they typically
have a harder time penetrating the surface and maintaining accuracy
compared to their split point counterparts.
In conclusion, for hardened steel, split point drills are generally
more effective while providing precision and reduced effort during the
drilling process.
Size and length of the drill
bit
The size and length of the drill bit play a crucial role when
drilling through hardened steel. Choose the size of your drill bit based
on the size of the hole you want to make. Common hard steel drill bit
sizes range from 1/16th of an inch to 1/2 an inch.
For thinner hardened steel, shorter lengths are suitable, which also
provide control during drilling. For deeper holes or thick steel pieces,
you may need to use a longer drill bit. However, longer bits tend to
wobble or bend during drilling, thus compromising precision. Therefore,
using drill bit sets offering varied lengths and sizes can cover most of
your drilling requirements. With trial and error, you can find the
perfect balance between the size and length of your drill bit for
maximum performance and longevity.
Durability
Durability is an essential factor to consider when selecting drill
bits for hardened steel. When drilling through tough materials such as
hardened steel, a bit’s durability determines how long it can maintain
its performance before it either breaks or becomes too dull to cut
efficiently.
Usually, the durability of a drill bit is directly tied to the type
of material it is made of. Hard metals such as cobalt and carbide are
extremely durable and can withstand the stress of drilling through
hardened steel. For instance, cobalt bits are highly resistant to heat
and wear, making them perfect for repeated use. Similarly, carbide bits,
while a bit more brittle, deliver an unmatched level of hardness and
wear resistance.
Another aspect to consider under durability is bit design. Features
like strengthened shank and fortified core can significantly enhance the
overall durability of the bit.
Lastly, not all work requires the most durable, and often more
expensive, bits. Evaluate your requirements; if you’re only drilling
through hardened steel occasionally, you might be more interested in a
balanced approach between durability, performance, and cost. But, if
your work involves drilling hard materials regularly, investing in
high-quality, durable bits can be more cost-effective in the long
run.
Coating
Coating is another key factor to look at when purchasing drill bits
for hardened steel. The coating can drastically improve the bit’s
performance and overall lifespan. Coated bits are more resistant to wear
and tear, can withstand higher temperatures and are less likely to rust,
all of which are significant when drilling through tough materials like
hardened steel.
There are various types of coatings available, but three of the most
common types are black oxide, titanium, and cobalt.
Black Oxide is a low-cost coating that reduces friction and increases
chip flow, which is beneficial when drilling through any material. It
also provides some resistance to corrosion. However, it may not be the
best choice for hardened steel due to lower heat resistance.
Titanium coating, often referred to as TiN (Titanium Nitride), helps
to increase the hardness of the drill bit and provides a thermal barrier
by reducing friction, which allows the bit to run cooler and last
longer. It’s a great choice for harder materials.
The Cobalt coating is not actually a coat but more of a fortifier.
These bits are comprised of solid cobalt alloy throughout, making them
exceedingly durable and resistant to heat.
In conclusion, considering the coating is crucial when selecting the
right drill bit for hardened steel. Remember, what you need is a bit
that can withstand high temperatures, display high performances, and
last under challenging conditions.
Review of the
Best Drill Bits for Hardened Steel
DEWALT Cobalt Drill Bit Set
Detailed product description
The DEWALT Cobalt Drill Bit Set is an excellent solution for drilling
through hardened steel. Offering an assortment of 14 pieces, ranging in
size from 1/16 of an inch to 3/8 of an inch, it provides options for a
myriad of drilling tasks. Each of the pieces in the set is crafted from
superior quality cobalt, renowned for its unparalleled durability and
resistance against heat, factors making it particularly suitable for
working on hardened steel.
Its high-performance discrete cobalt specs contribute to its
exceptional wear resistance during prolonged periods of drilling. The
drill bits in this set feature a Pilot Point tip design that ensures
effective work with lesser walk than the typical split point bits.
Moreover, this design reduces bit spinning in the chuck, ensuring better
performance and longer lifespan of the bits.
Each piece is designed thoughtfully to include a no-spin shank which
further increases the usability of the tool during heavy-duty tasks.
Coming encased in a robust plastic tough case, it provides secure
storage facilities, keeping the drill bits organized and safe for easy
transport and handling. The DEWALT Cobalt Drill Bit Set is truly
engineered to cater to professionals who work with hardened steel.
Benefits and drawbacks
The DEWALT Cobalt Drill Bit Set brings forth several noteworthy
benefits. The set includes drill bits made from industrial-grade cobalt,
which is renowned for its sturdiness, heat resistance, and long-lasting
performance. They are especially proficient at cutting through harder
materials like stainless steel and cast iron. The bits are designed with
a Pilot Point tip that starts on contact for a clean, accurate holes and
reduces lock-up on breakthrough. Their smaller size bits also have a
thicker web which allows for greater durability and longer life.
On the downside, these drill bits, although robust, are not immune to
wear and tear when used intensely over a longer period. Some users have
reported that the bits lost their edge after repeated use, particularly
when used on very hard materials. Additionally, the set, while
thoroughly comprehensive, does not include very large-sized bits, which
somewhat limits its versatility. The overall quality also comes at a
higher price point, making this set a premium option.
Bosch CO21B 21 Pc.
Cobalt M42 Drill Bit Set
Detailed product
description
The Bosch CO21B 21 Pc. Cobalt M42 Drill Bit Set is a durable,
high-performance set made specifically to drill through tough materials,
including hardened steel. Each bit is constructed from M42 Cobalt, which
is renowned for its robustness and longevity, ensuring each bit’s
effectiveness and durability when drilling through hardened steel.
This set contains 21 pieces, offering an array of sizes ranging from
1/16 inch to 1/2 inch in increments of 1/64 inch. This breadth of
diversity allows for flexibility in drilling different sized holes.
Designed with a split point tip, the drill bits reduce walking, which
increases accuracy and decreases the time spent working.
Unique to the Bosch brand is the special no-skate tip design that
provides accurate start-ups. The Hard Case that comes with the set
enhances the tidy storage of the drill bits, making it easy to keep
track of the bits and transport them safely. A web helix design is used
to remove material faster, and the bits are jobber length, intended for
a variety of drilling applications. These properties make the Bosch
CO21B Cobalt M42 Drill Bit Set a reliable choice for drilling through
hardened steel.
Benefits and drawbacks
The Bosch CO21B 21 Pc. Cobalt M42 Drill Bit Set offers an array of
benefits that make it a top choice for drilling through hardened
steel.
An undeniable advantage of this set is that it is made from Cobalt
M42 material. This implies that the drill bits are incredibly hard and
resistant to heat, reducing wear and tear and thus elongating their
lifespan, an essential factor for projects involving hardened steel.
Furthermore, the Bits are designed with a split point tip which
minimizes walking and allows controlled, clean, and accurate holes.
The set is also quite versatile, suitable for practically any tough
metal, not just hardened steel, thus making it an asset in any toolbox.
Additionally, the Bosch CO21B set comes with a sturdy case and 21 pieces
of varying sizes, giving users a broad spectrum of options for different
drilling requirements.
However, the Bosch CO21B 21 Pc. Cobalt M42 Drill Bit Set does have a
couple of drawbacks. While they perform exceptionally when used
correctly, these bits can be prone to breaking if mishandled, or put
under excessive stress or high drilling speed. The price point may also
be a concern for some users, given that it is somewhat higher than other
options in the market. However, the quality and durability of these
drill bits offer great value that offsets the initial cost in the long
run.
IRWIN Tools
Cobalt High-Speed Steel Drill Bit
Detailed product
description
The IRWIN Tools Cobalt High-Speed Steel Drill Bit is a well-regarded
drill bit specifically designed for hard materials, including hardened
steel. This drill bit is made from high-speed steel, known for its
durability, and has an industrially engineered 8% cobalt alloy that
ensures it maintains its strength even under extreme temperatures. It
features a heavy-duty spiral flute design that ensures efficient chip
ejection and keeps the workspace clean, reducing the risk of cracks.
Furthermore, the 135-degree split-point tip ensures a secure start
without skidding across the material, providing maximum control and
minimizing needed pressure. Each set features drill bits in a variety of
sizes, allowing for adaptability to different project needs.
Benefits and drawbacks
The IRWIN Tools Cobalt High-Speed Steel Drill Bit is one on our list
offering multiple benefits for drilling through hardened steel. One of
the most significant advantages is its cobalt construction, which equips
the bits with high-heat resistance and strength, making them suitable
for demanding projects. The bits’ 135-degree split-point tip design
reduces slipping when starting, which can increase efficiency and reduce
effort.
Moreover, these bits come in a heavy-duty metal case, keeping them
organized and secure from potential damage. The set also includes a wide
variety of sizes, which provides versatility for different tasks.
Lastly, the product’s extended lifespan is a big plus, especially
considering the demanding nature of drilling through hardened steel.
However, despite numerous advantages, the product also exhibits a few
drawbacks. Some users have reported bits breaking after repeated use,
which may stem from defects in manufacturing rather than a reflection on
the overall quality of the product. Additionally, the cost of this drill
bit set is relatively high compared to some others on the market. This
may be disadvantageous to those operating on a tight budget, but it’s
worth keeping in mind that investing in high-quality tools can often
save money in the long run.
Drill America M35 Cobalt
Drill Bit Set
Detailed product
description
The Drill America M35 Cobalt Drill Bit Set is an excellent set
designed specifically for tough drilling jobs such as hardened steel,
cast iron, stainless steel, and other hard metals. The set consists of
29 pieces, each made out of M35 cobalt steel alloy. This alloy
composition provides the bits with superior hardness and heat
resistance, making them the go-to set for challenging drilling
tasks.
Each bit in the Drill America set features a self-centering
135-degree split point design that effectively reduces walking while
drilling. The split point also helps to penetrate tough materials faster
without the need for a pilot hole. The bits range in size from 1/16-inch
up to 1/2-inch, offering a wide variety for any drilling job you might
encounter.
These bits have a gold oxide finish, which not only adds an aesthetic
appeal but also enhances durability, reduces friction, and increases
chip flow. They also come in a convenient metal storage case for easy
organization and transportation.
The Drill America M35 Cobalt Drill Bit Set is designed for use in
heavy-duty spiral fluted tools, offering increased strength, better heat
and wear resistance, and a longer lifespan, making it perfect for
drilling through hardened steel. The bits meet or exceed Nation
Aerospace Standard (NAS) 907, demonstrating the quality and reliability
of this set.
Benefits and drawbacks
The Drill America M35 Cobalt Drill Bit Set offers several advantages
that make it a great addition to your toolbox. Most notably, these drill
bits are made from M35 cobalt steel, known for its high heat resistance
and durability. They can withstand the extreme temperature that comes
with drilling through hardened steel, which significantly reduces the
risk of damage or breaking. The set includes a variety of sizes,
providing versatility for different applications. Another advantage is
their 135-degree split point, which prevents walking and allows for more
accurate drilling.
However, there are a few drawbacks to consider as well. The main
drawback is their price point. Being high performance tools, they tend
to be more costly than other drill bits on the market. Another potential
issue is the absence of a holder for the bits. This might lead to
possible misplacement or loss of smaller sizes if not stored properly.
Lastly, while they are exceptionally good at drilling through hardened
steel, they might be overkill for softer materials, so they may not be
the most economical choice if you need drill bits for various
materials.
Neiko 10197A Titanium
Step Drill Bit Set
Detailed product
description
The Neiko 10197A Titanium Step Drill Bit Set stands out as an
excellent choice for drilling through hardened steel, thanks to its
robust design and top-tier materials. This set includes five pieces of
drill bits with different sizes, ranging from 1/4 inch to 1-3/8 inches,
strategically layered to perform multiple functions.
Each bit is crafted from classic high-speed steel (HSS), which is
renowned for its durability and resistance to heat. The drill bits are
further enhanced with a titanium coating that significantly increases
their lifespan, providing longevity under frequent use.
One of the key unique features of the Neiko 10197A is the two-flute
design which reduces friction and heat. This is beneficial because it
allows for smoother, faster drilling and prevents damage to both the
drill bit and the material being drilled.
The drill bits also include a tri-flat shank design. This design
allows for a secure grip and stops the drill bit from slipping in the
drill chuck.
In terms of compatibility, this set can be used with both cordless
and stationary drills, making it versatile and suited for a wide range
of drilling projects. The case included with the set is well-organized
and durable, keeping the drill bits safe and easy to transport.
Benefits and drawbacks
Benefits:
Neiko 10197A Titanium Step Drill Bit set is renowned for its strength
and durability due to the high-speed steel used in their construction,
which is further enhanced by a titanium coating. This makes the drill
bits capable of withstanding high temperatures while maintaining their
sharpness.
Another noted benefit is that the set includes 5 pieces of step drill
bits, which means each bit covers several sizes. This eliminates the
need for having separate bits for each hole size, making it a space and
cost-efficient choice.
These drill bits are also praised for their versatility. The
two-flute design allows for cleaner, smoother drilling, and their
compatibility with a variety of materials, not just hardened steel, is
impressive.
Drawbacks:
Despite having numerous advantages, a few drawbacks are also
associated with the Neiko 10197A Titanium Step Drill Bit Set. The
primary concern for users is that while this set works well for various
materials, it may not be the most efficient choice for heavily hardened
steel. For everyday applications, it performs well, but for more
challenging, industrial-level tasks, it might struggle.
Another possible limitation could be the bit sizes provided in the
set. Albeit useful for most of the tasks, in certain specific
applications where uncommon sizes could be required, this set might not
be sufficient.
In summary, the Neiko 10197A Titanium Step Drill Bit Set is a
versatile and reliable selection for most applications. However, for
more heavy-duty tasks, especially in industrial settings, other
specialized options may be preferable.
Tips for Drilling
Through Hardened Steel
Correct drill speed
Using the correct drill speed is crucial when working with hardened
steel. This is because different materials require varying speeds to
effectively drill through them without causing damage to either the
material or the drill bit. For hardened steel, a slow drilling speed is
typically recommended.
Keep in mind that the slower speeds help to reduce the heat generated
when drilling. High temperatures from rapid drilling can potentially
burn out your drill bits and even change the properties of the steel. A
recommended speed for drilling into hardened steel is often between 80
to 200 RPM, depending on the hardness of the steel and the size of the
drill bit.
Typically, smaller drill bits require a faster rotation speed
compared to larger ones. Therefore, a key tip to remember is always
starting off slow then adjusting speed as necessary through the drilling
process to maintain the bit’s life expectancy and effectiveness. Always
refer to the drill bit manufacturer’s guidelines for optimal speed
information. Remember – slow and steady often wins the race when
drilling into hardened steel.
Lubrication
Lubrication is a critical element when it comes to drilling through
hardened steel. By using cutting fluids or lubricating oils, you’ll be
able to reduce the friction between the drill bit and the surface of the
steel. This not only prevents the drill bit from overheating but also
extends the lifespan of the bit by reducing wear and tear. Lubrication
also aids in clearing out the chips and debris that are produced during
the drilling process, reducing the risk of clogging. You should
regularly pause your drilling, apply lubricant, then continue to drill.
Remember, consistent lubrication results in a cleaner, smoother hole,
and ensures a significantly easier drilling process.
Gradual progression in
drill bit sizes
Drilling through hardened steel is a task that requires patience and
precision. In this regard, working up through a gradual progression of
drill bit sizes can be quite beneficial. This process, often known as
step drilling, involves starting the hole using a small diameter bit and
then slowly increasing the bit size until the desired hole diameter is
achieved.
Step drilling can help avoid overheating and breakage of the drill
bits, prolonging their lifespan. It also creates a more accurate hole,
as the smaller pilot hole guides the larger bits, improving the
precision and alignment of the final hole.
However, it’s vital to allow the drill bit to cool and be properly
lubricated between each step. Doing so can further protect your bit from
potential damage, giving you the smooth and efficient drilling
performance necessary for working with hardened steel.
Remember, drilling through hardened steel can be a challenging task,
but with a strategic approach like gradual bit progression, it can
become much more manageable. Drilling should be done carefully and
patiently, ensuring that your tools and efforts aren’t wasted and
yielding the best possible results.
Keeping the drill bit cool
Keeping the drill bit cool is paramount when drilling through
hardened steel. The heat that is produced by the friction between the
drill bit and the surface can cause the drill bit to overheat, which in
turn can reduce its efficiency and potentially cause damage.
One effective way to keep the drill bit cool while working is through
a process known as ‘peck drilling’. This involves drilling for a short
period, then retracting the bit to allow it to cool down and the debris
to escape. Repeat this process until the hole is completed.
Another useful method is the use of a coolant or cutting fluid. These
are specially formulated liquids that will not only help to reduce the
heat but also improve the cutting performance and extend the life of the
drill bit. They can either be applied directly to the drill bit or to
the surface being drilled.
Remember, drilling at a slower speed can also help to minimize
overheating. When drilling through hardened steel, it’s not about how
fast you can complete the job, but rather taking the time to ensure it’s
done well while preserving your tools and achieving the best quality
finish.
By keeping these tips in mind, you can help to maintain the condition
and efficiency of your drill bits, allowing them to last longer and
perform more effectively in your various DIY or professional
projects.
Conclusion
Recap of the best drill bit
options
After an in-depth review of various offerings in the market, we have
identified some standout choices for the best drill bits for hardened
steel. The DEWALT Cobalt Drill Bit Set is an excellent option for those
seeking durability and precision. The Bosch CO21B 21 Pc. Cobalt M42
Drill Bit Set provides professional-grade performance, while the IRWIN
Tools Cobalt High-Speed Steel Drill Bit stands out for its versatility
and speed. For those who need a wide variety of sizes, the 29-piece
Drill America M35 Cobalt Drill Bit Set is a top choice. Finally, the
Neiko 10197A Titanium Step Drill Bit Set is laudable for its unique
design that caters to different hole sizes with a single bit.
Regardless of the project, remember to always prioritize using the
right tools. The correct drill bit can make the difference between a
smooth, efficient process and a challenging, potentially damaging one.
Make sure to consider the material, shape, size, durability, and coating
when choosing a drill bit and adjust your drilling technique accordingly
to achieve the best results.
Brief
advice on the importance of using the right tools for any project
Choosing the right tools for any project is crucial not only for the
success of your work but for your own safety as well. Remember that
little details make a big difference, and this holds true for tasks as
simple as choosing the right drill bit for the job. The right bit can
save you time, effort and can give you a neat and successful output. It
can also reduce the chances of damaging the workpiece, your tools, or
yourself. So whether you’re a professional tradesperson or a DIY
enthusiast, do your research, consider your needs, and invest in quality
bits. It will be worth it in the long run.
References
Cite sources of information
[1] “Understanding Drill Bit Materials and Designs.” Tooling U-SME.
www.toolingu.com (Accessed April
25, 2021)
[2] Charles, Steve. “Drilling through Hardened Steel: The Right Drill
Bits for the Job.” Metal Production Journal, www.metalproductionjournal.com
(Accessed April 26, 2021)
[3] DEWALT Cobalt Drill Bit Manufacturer Specifications. DEWALT
official website. www.dewalt.com
(Accessed April 27, 2021)
[4] Product Description and Reviews, Bosch CO21B 21 Pc. Cobalt M42
Drill Bit Set. Amazon.com. www.amazon.com (Accessed April 27,
2021)
[5] IRWIN Tools Cobalt High-Speed Steel Drill Bit Product
Information. Irwin Tools official website. www.irwin.com (Accessed April 27,
2021)
[6] Review and Specs, Drill America M35 Cobalt Drill Bit Set. Drill
America official website. www.drillamerica.net (Accessed
April 28, 2021)
[7] Product Description and Reviews, Neiko 10197A Titanium Step Drill
Bit Set. Amazon.com. www.amazon.com
(Accessed April 28, 2021)
[8] “The Ultimate Guide To Drill Bits.” Popular Mechanics Magazine.
www.popularmechanics.com
(Accessed April 29, 2021)
[9] “Cobalt vs. Titanium Drill Bits: Choose the Right One for Your
Job” Home Tools Guide, www.hometoolsguide.com
(Accessed April 29, 2021)
[10] Anderson, Luke. “Drilling 101: How to Drill Through Hardened
Steel.” Machine Workshop manual. www.machineworkshopmanual.com
(Accessed April 30, 2021)
Note: The URLs are imaginary, created for the purpose of this
fictional reference section. In a real-world setting, ensure you use
actual, valid URLs or citation data.
