M7 vs M42 Drill Bits – 2021 Review

| Last Updated: June 29, 2021

When using drill bits to cut into surfaces, you can use the standard high-speed steel (HSS) drill bits for when you’re dealing with wood and soft-metal surfaces. However, the problem arises when you’re dealing with stainless steel and other types of heat-hardened metals. This is where the standard HSS drill bits are of no use. 

Therefore, in such a case, what you really need are cobalt drill bits constructed using stronger materials. This makes them more durable and heat-resistant compared to the average bits. They are perfect as you can use them on different kinds of metal surfaces, and even if they were to lose their edge, all you have to do is sharpen them, and that's it! You can continue on with your work. 

Now, the market is filled with different options, which makes it difficult to choose the right one. Therefore, we have reviewed some of the best drill bits that you should definitely check out before you make your purchase. 

Comparison Chart of the Best M7 and M42 Drill Bits

  • Best M7 Drill Bits
  • Made from very durable M7 steel to last longer
  • Comes with a lifetime warranty included for peace of mind
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  • Best M42 Drill Bits
  • Premium cobalt high-speed steel used in manufacturing
  • The 135 degrees split point will prevent walking
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What is an M7 Drill Bit and What is it Best For?

The M7 drill bit is primarily used for the making of heavier construction drills. It is made using Hi-Molybdenum M7. It offers you great flexibility and has an extended drill life, which is required when dealing with heavier construction drills. M7 molybdenum steel tools are required for cutting tools in all of the machining operations. 

What sets the M7 apart is the fact the steel offers excellent abrasion-resistance due to all of the carbon and vanadium contents being used. Such drill bits are an excellent choice for all kinds of premium tools that feature red hardness, require an edge toughness and be wear-resistant. It is suitable for machining semi-hard surfaces, such as heat-treated steel. 

What is an M42 Drill Bit and What is it Best For?

M42 drill bits are made using eight percent cobalt, which helps in increasing their strength, making them heat- resistant. This allows such bits to be used when dealing with hard materials. It is a specialized drill bit and can be used for drilling surfaces, including stainless steel, cast iron, titanium, and other abrasive metals as well. 

M42 is for drilling hard materials, as the additional cobalt gives it more strength. Such drill bits are also used for machining hardened alloys and other tough materials. 

What is the Drill Bit M42 Rating Specification?

M42 is similar to M35 and M2; however, the thing that sets it apart is that it contains eight percent cobalt. This makes it a specialized bit, making it more brittle than M35. The extra cobalt helps by enhancing the heat-resisting capacity and durability.  

M7 vs M42 Drill Bits Similarities and Differences 

Now that you know a little bit about the two drill bits, the question is, which one should you use? While both are effective and efficient, it is better to understand which one would be better for what purpose. Here we have drawn up some comparisons between the two drill bits so that you can fully understand the similarities they have and what really sets them apart. 

M7 and M42 Drill Bits Similarities

Some similarities between the two bits include:

  • While all HSS happen to be high-moly, both M7 and M42 contain more moly than others. This helps to make both harder and gives them greater strength. 

  • Both drill bits tend to last for a longer period of time. 

M7 and M42 Drill Bits Differences

A few differences between the two bits include:

  • M7 drill bits have more moly, whereas M42 drill bits have more cobalt in addition to more moly.

  • M42 has a comparatively higher heat and abrasion resistance. 

Top Pick Between M7 and M42 Drill Bits

M7 and M42 are required when dealing with hard materials. This separates them from the other bits available in the market. They are suitable for premium tools; however, the better one to opt for would be the M42. This is because it has eight percent cobalt, which makes it more durable. It also offers better heat resistance.

M42 drill bits are harder and can be used at higher cutting speeds. Moreover, they’re comparatively more brittle, which makes it easier to break them. These drill bits offer increased water resistance and longer tool life as well. You can use the M42 when working with hardening alloys and other tough materials. 

Overview of Our Favorite M7 and M42 Drill Bits

Once you have decided the kind of drill bit you want, then comes the task of choosing the right model. There are many different options available in the market from different manufacturers, which makes it difficult to choose the right one.

Therefore, we have reviewed some of the best options available for you to consider. 

Best M7 Drill Bits:
Drill Hog Hi-Molybdenum M7 Drill Bit Set

Drill Hog 21 Pc Drill Bit Set Index Hi-Molybdenum M7


  • Accurately grounded
  • Features razor-sharp tips 
  • Can easily drill through hard materials
  • Offer you a solid grip to prevent slippage 


  • Quality isn’t consistent 

What Recent Buyers Report

According to most buyers, the Drill Hog 21 Pc Drill Bit is a great option, as it allows you to tackle hard metals, including stainless steel. It features razor-sharp tips, which makes it easier to drill through hard surfaces. It also comes with faceted shafts that provide you with a strong grip so that there is no chance of any slippage. 

Why it Stands Out to Us

The Drill Hog drill bits feature advanced technology. The bits are made using Hi-Molybdenum M7. They have a melting point of nearly 5000 degrees Fahrenheit, which makes them heat-resistant. They are capable of drilling through tough steel and other metals that can be found in a truck frame, stainless steel, forging, farm implements, spring steel, etc.

Bottom Line

All in all, these Drill Hog drill bits are a good option, especially when you’re dealing with extremely hard materials as they are capable of drilling through such surfaces easily. They offer effective drilling when dealing with premium tools and are an option worth considering.

Best M42 Drill Bits:
Drill Hog M42 Cobalt Drill Bit Set

Drill Hog 29 Pc Cobalt Drill Bit Set M42 Drills


  • Sharp tips
  • Premium drill bit
  • Drilling requires less effort
  • Extremely high melting point 


  • Quality consistency issue 

What Recent Buyers Report

As per reports, these drill bits are some of the best ones available. You get what you are actually paying for. They help make the drilling process a lot easier, even when dealing with hard metals. All in all, users are pretty impressed with these. 

Why it Stands Out to Us

This M42 Cobalt Drill Bit Set by Drill Hog features the newest technology, and the drill bits are made using Cobalt M42 Steel. They have a melting point of about 2,853 degrees Fahrenheit and can be used to drill the toughest steel. You can use them for truck frames, stainless steel, spring steel, farm implements, grade 8 bolts, etc. 

Moreover, these drill bits feature a tri-flat shank to prevent the chuck from spinning. They feature a hardness of about 68-70 HRC and offer you a 135-degree split point. 

Bottom Line

The Drill Hog M42 Cobalt Drill Bits are effective and efficient when it comes to drilling hard metals and other materials. They are heat-resistant and have razor-sharp tips. They are made using premium-quality solid cobalt high-speed steel, which makes them a durable option to consider.


M7 and M42 drill bits offer excellent drilling performance. They are effective when dealing with strong metals, making them a great candidate for heavy construction drills and machining hard alloys. They are heat-resistant, have sharp tips, and help make the whole process a lot easier. 

While there are other types of drill bit models available in the market, these two are durable and have great strength; therefore, if you’re looking to buy some drill bits, you should definitely consider checking them out.