Cobalt vs HSS Drill Bits – 08 Quick Facts!

When we consider Cobalt Vs HSS drill bits, we can see a clear difference between them. Both are used for tough drilling tasks such as drilling steel, cast iron, stainless steel, etc. When you select one of them you should know which one is suitable for your task. So let’s compare all detail under 08 facts.

Cobalt Vs HSS Drill Bit Comparison Table

When we compare cobalt vs HSS drill bits, we have to consider each feature of the drill bits. Below table includes summarize detail about the Cobalt and HSS drill bit comparisons.

Cobalt Drill BitsHSS Drill Bits
ColorDark golden amber finishedBright fnished
Manufactured materialHigh-speed alloy steel, which contains 5%-8% cobalt➤ Tungsten – 15%
➤ Chromium – 5%
➤ Vanadium – 1%
➤ Carbon – 0.7%
Applied coatingThere is no outer coating.Bright finished
Market priceExpensive than the HSS drill bits. 
$10 – $200
Economical than the Cobalt drill bits. 
$7 – $60
UsageCobalt drill bits are mostly used to drill the hardest metals. HSS drill bits are mostly used to drill soft materials
UtilityCobalt drill bits are less multipurpose. Because can not drill the plastic and wood by using Cobalt drill bits.HSS drill bits are more multipurpose. Because this can br used to drill hard metals, wood, plastic, etc.
Required RPM500 RPMRPM = (3.8197 / Drill Diameter) x SFM
Hardness65HRC (approximately)60 HRC – 68 HRC (approximately)
SharpingSharping process is easier than the HSS drill bit because there is no any outer coating.Sharping process is a little bit more difficult than the Cobalt drill bit because there are several outer coatings.
BrittlenessCobalt drill bits break easily. Because it is more brittle.HSS drill bits don’t break easily because it is more elastic.
Thermal resistanceThermal resistance is high than the HSS drill bits.Thermal resistance is less than cobalt drill bits
DurabilityDurability is high than the HSS drill bits.Durability is less than cobalt drill bits.
Cobalt drill bit Vs HSS drill bit comparison

You May be Interested to Read About

Features of Cobalt Drill Bits

Cobalt Drill Bit
Cobalt drill bit

1. Color

  • Dark golden, Amber finished

Color is one way to identify the Cobalt Drill Bits.

  • Cobalt drill bits are burned during the manufacturing process. Accordingly, this color occurs during the manufacturing process. Therefore, this color is not plating or paint.

2. Manufactured material

High-speed alloy steel which contains 5%-8% cobalt. Accordingly, this is not made by using pure cobalt.

This alloy has high:

  • Hot corrosion resistance
  • Melting point
  • Thermal weldability
  • Fatigue resistance

Therefore, these Cobalt Drill Bits are tougher and stronger for the hardest metals. Moreover, it has a longer life because of this material.

Cobalt drill bits can be divided into different types according to the percentage of cobalt in the drill bit. For example:

  • M35 – Contains 5% cobalt (approximately)
  • M42 – Contains 8% cobalt (approximately)

3. Applied coating

Cobalt Drill Bits have no outer coating. Therefore, these drill bits are easy to sharpen. Accordingly, it is led to prepare a sharp drill bit easily. Moreover, it has high efficiency. Because there is no coating to be peeled off. That led to an increase in the efficiency of this drill bit.

Drill bits coatings can increase the durability of the tool and decrease friction, resistance, and thermal resistance. So you should pay attention when you buy a drill bit with coating.

4. Market price

Generally, cobalt drill bits are more expensive. Although, it is better than most other types of drill bits.

5. Usage

As mentioned earlier, Cobalt drill bits are tougher and stronger for the hardest metals such as:

  • Stainless steel
  • Cast iron
  • Non-Ferrous
    • Bronze/Brass
    • Aluminum Alloys
    • High Silicon
    • Copper
  • High-temperature alloys
    • Nickel Base
    • Titanium
  • Welding seams

Moreover, this can be used under conditions such as high temperatures. Because it has high boiling as well as melting points.

However, this does not applicable for general applications such as light metal, wood, and plastic. Because cobalt drill bits are brittle. Therefore, it can break easily. Moreover, this is not good for the use drilling of the concrete.

6. Required RPM

  • 500 RPM (approximately)

7. Hardness

  • 65HRC (approximately)

Cobalt drill bits are harder than most other types of drill bits. Moreover, these drill bits do not get the hardness by using the coating.

Because there is no coating, accordingly, it gets the hardness from the entire material. Therefore, its hardness is uniform. However, it is also brittle. Because if the cobalt content is higher and the harder it is, the more likely it is to break.

These are the 09 reasons for the drill bits breaking. So avoid these things in your drilling process.

8. Sharping

Cobalt bits can sharpen again and again. That is better to do that before drilling some material. Because that is led to drilling more efficiently and effectively.

Moreover, that is also economically sound. Because there is no need to buying a new bit. However, sharping tools are a little bit expensive. Additionally, broken parts of the drill bit can damage the user and take a long time to finish.

Therefore, sharpening these bits at the required time is really important in many ways. Because that ensures maximum results and does the task timely manner. There are several steps in the re-sharpening process.

This is my favorite method for sharpening drill bits.

Drill Bit Sharpening Process
Drill Bit Sharpening Process

Features of HSS Drill Bits

HSS Drill Bit
HSS Drill Bit

1. Color

  • HSS drill bits are color in black (Most of the time), Bright, Amber finished, Ti-Coated

This is the best way to identify the drill bits. This color helps to:

  • Increase the thermal resistance
  • Increase the abrasion resistance

There is use some special coatings also such as TiN, TiCN, TiAIN

2. Manufactured Material

Simply, it is high-carbon steel. However, this HSS alloy contains several elements, such as:

  • Tungsten – 15%
  • Chromium – 5%
  • Vanadium – 1%
  • Carbon – 0.7%

Although, these percentages vary according to the types of HSS drill bit. For example:

Types of HSS Drill Bits

Hardness can be varying according to these material proportions. Most of the time, HSS drill bits are made with M2 type.

3. Applied Coating

There are several coatings applied in these HSS drill bits. Those are:

  • Titanium Nitride – TiN
  • Titanium Carbon Nitride – TiCN
  • Titanium Aluminum Nitride – TiAIN

These coatings are led to an increase performance. Because by using these coatings can:

  • Increase the heat resistance
  • Increase the durability of the drill bit
  • Reduce the friction of the drill bit
  • Prevent corrosion

Enhance the durability of the drill bit.

4. Market Price

This HSS drill bit is cost-effective.

5. Usage

These HSS drill bits can be used to drill several sizes of holes on different materials. Generally, these HSS drill bits are used to drill soft materials. For example:

  • Mild steel
  • Cast iron
  • Aluminum
  • Fiber
  • Plastic
  • Brass
  • Hardwood
  • Softwood

Moreover, this is can also use to drill the hardest metals if the drill bits are coated. For example:

  • Cast iron

Although, usage of HSS drill bits varies according to the type. For example:

M1General purpose
M2Knives, Twist drills, Taps, Broaches
M7Heavy construction equipment
Usage Of HSS Drill Bits

6. Required RPM

Users need to know about the SFM (Recommended speed) to calculate the RPM. Accordingly, RPM can be calculated by using:

RPM = (3.8197 / Drill Diameter) x SFM

Accordingly, this table gives the SFM of a few materials.

Brass150 – 300
Aluminum200 – 300
Plastic100 – 300
Material With SFM values

8. Hardness

  • 60 HRC – 68 HRC (approximately)

As mentioned earlier, hardness can be varying according to these material proportions. Moreover, the hardness of HSS drill bits also depends on the process of heat treatment.

9. Sharping

HSS drill bits can be easily sharped. There are a few conditions under which the user may recognize that drill bits must be sharp. Those are:

  • Drilled holes are out of the tolerance
  • Produces more noise when drilling
  • Chipping length is below 0.02

The user can use a carbide grinder, diamond grinder, bench grinder, or a file to sharpen the drill bits. Although, the user should to consider and maintain the cutting angle the most. Because the cutting angle varies according to the material requirement, there are three types of angles.

When you use a drill bit you can see at least one of these 08 problems of drill bits. I have listed all 08 drill bit problems and solutions here.

  • Point Angle
  • Helix Angle
  • Lip Relief Angle

This table gives the details of how much needs to be sharp in the angles of a few materials.

Point Angle90 – 11890 – 13560 – 90
Helix Angle0 – 2032 – 480 – 20
Lip Relief Angle12 – 2612 – 2612 – 26

It is necessary to sharpen the drill bits at the right time. Because dull drill bits are led to overheating, accordingly, it is led to reducing efficiency. Moreover, it is economically sound if the user sharpens the drill bits at a right time because the re-sharping process helps to extend its life.

A drill bit will hot due to these 09 reasons and you can cool the drill bit using these 07 tips

HSS or Cobalt Drill Bit – Which One Do You Need?

Cobalt vs HSS Drill Bit
Cobalt vs HSS Drill Bit

Accordingly, there are several factors is need to be considered before purchasing a drill bit. Initially, the user must consider what material is going to be drilled.

Moreover, the user should also consider their budget. However, HSS drill bits are multipurpose. Because it can drill steel and even plastic and wood. Furthermore, cobalt drill bits are more durable than HSS drill bits.

Heat is generated during the drilling operation. Cobalt drill bits have higher heat resistance than the HSS drill bits. Therefore, the sure should also consider the heat resistance.

Additionally, the user should be careful about their safety while using these. For that users can wear protective goggles, face shields, and gloves.

Therefore, choosing a drill bit is a little bit difficult. It is the user’s responsibility to choose the right drill according to their needs, use it correctly and cleanly and sharpen it at the right time.

Tom Mackency

Tom Mackency

Hi, I am Tom Mackency. It has been 10 years that I have been working as a professional woodworker since 2013. I am really enjoying my carrier by creating many kinds of projects in my workshop. But mostly I like for home improvement projects. Home improvement and DIY projects are the most interesting things for me. More than that, the coolest things are power tools. Those are very precious and efficient than a decade ago. So I try to introduce so many things about power tools, woodworking, DIY projects, home improvement and many more interesting topics here.