M2 vs M35 vs M42 HSS Drill Bits: What Is the Difference?

M2, M35, and M42 are three common high-speed steel grades used for drill bits. The main difference is their alloy composition, particularly cobalt content, which affects heat resistance and performance in demanding drilling applications.

For general-purpose drilling, M2 HSS is widely used. M35 and M42 are more often selected when higher heat resistance and cutting performance are required.

M2 HSS: A Versatile General-Purpose Option

M2 is a widely used high-speed steel for twist drill bits and other cutting tools. It offers a practical balance of hardness, wear resistance, toughness, and cost.

M2 HSS drill bits are commonly used for:

• Mild steel
• Carbon steel
• Aluminum
• General workshop applications
• Maintenance and repair

For standard metal drilling, M2 can provide reliable performance without the additional material cost of cobalt-containing HSS grades.

M35 HSS: Added Cobalt for Higher Heat Resistance

M35 HSS contains approximately 5% cobalt. The addition of cobalt improves hot hardness and allows the cutting edge to maintain its properties at higher temperatures.

M35 is commonly considered for:

• Stainless steel
• Alloy steel
• Harder metals
• Repeated drilling
• Professional metalworking

For applications where standard M2 HSS may experience faster wear under heat, M35 can provide a useful step up in performance.

M42 HSS: For More Demanding Drilling

M42 HSS contains approximately 8% cobalt, giving it higher hot hardness and heat resistance than M2 and M35.

It is commonly used for more demanding drilling applications, including harder steels, stainless steel, and other difficult-to-machine materials.

The higher cobalt content also increases material cost, so M42 is not necessarily the most economical choice for routine drilling.

The table is a general product-positioning reference. Actual drilling performance also depends on point geometry, heat treatment, grinding accuracy, surface treatment, machine conditions, and cutting parameters.

Which HSS Grade Should You Choose?

For routine metal drilling where cost and versatility are important, M2 HSS is often a practical choice.

When drilling stainless steel or harder materials more frequently, M35 HSS can offer additional heat resistance.

For demanding applications involving higher temperatures, harder workpieces, or extended cutting, M42 HSS may be more suitable.

A higher-grade material is not automatically the better choice. The specification should match the workpiece, drilling conditions, expected tool life, and target cost.

One-Stop Drill Bit Sourcing

TOOLJOY provides one-stop sourcing for drill bits and related tool products, with options covering HSS grades, sizes, geometries, surface treatments, packaging, and OEM/ODM requirements.

For distributors and brands, different HSS grades can be developed as separate product levels, making it easier to cover general-purpose, professional, and higher-performance applications within one product range.

For a broader comparison of 4241, 4341, M2, M35, and M42, see our first News article: “4241 vs 4341 vs M2 vs M35 vs M42 HSS Drill Bits: How to Choose?”

FAQ

1.What is the main difference between M2, M35, and M42 HSS?

The main difference is alloy composition, particularly cobalt content. M35 contains approximately 5% cobalt and M42 approximately 8%, providing higher heat resistance than standard M2 HSS.

2.Is M42 better than M35?

M42 generally offers higher hot hardness and heat resistance, but it also costs more. M35 may be sufficient for many professional drilling applications.

3.Which HSS drill bit is suitable for stainless steel?

M35 and M42 are commonly considered for stainless steel drilling, especially when heat and wear are concerns. M2 can also be used for suitable applications with proper drilling conditions.

4.Why are M35 and M42 more expensive?

Their cobalt content increases material cost and provides improved hot hardness and heat resistance, making them suitable for more demanding applications.