While choosing an end mill tool for a table top CNC machine, its nature and composition play a crucial role in determining performance, accuracy, and machining speed. High-speed steel and carbide end mills have been in a constant battle to outdo each other based on multiple metrics.

If you are stuck between having to choose between the two, this post can help you make an informed decision on which of these can be a better choice. On that note, let’s dive right in!

High-Speed Steel vs. Carbide: A Brief History

Before getting into the details of the differences between high-speed steel and carbide end mills, let us get an overview of the basics of the tools.

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High-speed steel tools came into use somewhere in the 1930s. HSS tools revolutionized the cutting and milling standards as they were considered tougher, more durable, and highly versatile. They could cut through a wide array of metals, making them a worthwhile investment.

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On the other hand, carbide tools were an alternative to diamond cutting. They were a result of the combination of cobalt and tungsten carbide, which was subject to heat and pressure for compaction and strengthening of material.

Interestingly, the use of carbide blades precedes HSS blades. And while HSS tools bore a significant advantage above their carbide counterparts at one point, the former made a comeback thanks to the advancements in their design and technologies. Modern-day carbide tools are many folds stronger than their counterparts produced centuries ago.

High-Speed Steel vs. Carbide End Mills: A Head-to-Head Performance Measurement

Based on a diverse set of parameters, here is a detailed comparison between high-speed steel versus carbide end mills:

1. Heat Tolerance

Machining activities, such as drilling and boring, generate high degrees of heat. Overheating is a serious issue that operators cannot neglect since it could have serious repercussions such as tool deformation or reduction in tool lifespan. As such, it requires proactive temperature regulation through constant monitoring while also setting up cooling mechanisms.

Carbide end mills enjoy higher heat tolerance due to their inherent higher thermal resistance. As a result, they can deliver high performance without any loss of shape or performance. Hence, if you are working at high temperatures, a carbide tool could suit your needs regardless of your skills and expertise.

2. Toughness

In addition to being heat resistant, carbide end mills are also tougher in general. The toughness of carbide tools lends immense versatility to it and allows it to bore or tap through a wide range of materials. As a result, experts recommend carbide end mills for handling repurposing projects. Further, they suggest using carbide bits for boring through materials that will result in large volumes of dust and debris.

3. Durability

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The combination of heat resistance and toughness make carbide blades more durable, thereby elongating their tool life. Its long-lasting nature makes it well worth the investment. However, if you are looking for a disposable tool that you can quickly do away with, HSS end mills would be a better choice.

4. Finishing

The end mill determines the milling, boring, and tapping action, which in turn affects the finishing and the end result of the workpiece. Defects such as burrs not only take away the visual appeal of the finished product but also pose as a hazard or obstacle in the part’s performance. And since machining could play a crucial role in the compatibility of the parts, obtaining clean, smooth, and accurate finishing may be a high priority.

Fortunately, carbide end mills can deliver such results. The toughness and heat resistance of carbide mills allow the operator to focus on the machining action and ensure smoother and more polished finishing.

5. Sharpening

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When it comes to tool maintenance, tools like end mills have to be sharpened and calibrated frequently. Since HSS tools tend to wear off quicker, they may require frequent sharpening. But on the plus side, they are easier to sharpen.

On the other hand, carbide mills require sharpening less frequently, but you will have to use a dedicated carbide sharpener to achieve the desired result, which can be quite pricey.

6. Cost

A quick glance at the market rate indicates that high-speed steel mills are more affordable than carbide end mills. And if one only thinks of the upfront cost, HSS could be a pocket-friendly alternative. In fact, they could serve as an excellent tool for beginners who can practice their skills without worrying about breakages and replacements.

However, if you are quantifying the cost through variables like durability and toughness, which affect the tool’s longevity, then carbide tools could be more suitable for trained professionals and veterans.

Final Thoughts

The above comparison can help you determine whether you should go for high-speed stainless steel or carbide end mills. While carbide blades rack up more points, high-speed steel also has its moments when it outshines.

That being said, you will have to make the choice depending on the application and project requirements. And regardless of which tool you pick, you will have to care for it and maintain it in the long run to derive its associated benefits. 

About the Author:

Peter Jacobs

Peter Jacobs is the Senior Director of Marketing at CNC Masters. He is actively involved in manufacturing processes and regularly contributes his insights for various blogs in CNC machining, 3D printing, rapid tooling, injection molding, metal casting, and manufacturing in general.