Content Menu
● Introduction to Tungsten Carbide Drill Bits
>> Characteristics of Tungsten Carbide Drill Bits
● Sharpening Tungsten Carbide Drill Bits
>> Tools Needed for Sharpening
>> Steps to Sharpen Tungsten Carbide Drill Bits
● Challenges and Considerations
>> Cost and Accessibility of Diamond Tools
>> Professional Sharpening Services
● Alternative Sharpening Methods
>> Silicon Carbide Wheels
>> Electrical Discharge Machining (EDM)
>> Laser Sharpening
● Sharpening Angles and Geometry
>> Point Angle and Lip Relief Angle
● Cryogenic Treatment for Extended Lifespan
● Conclusion
● FAQ
>> 1. What is the best tool for sharpening tungsten carbide drill bits?
>> 2. Can I sharpen tungsten carbide drill bits myself, or should I hire a professional?
>> 3. What are the key angles for sharpening standard twist drill bits?
>> 4. How often should tungsten carbide drill bits be sharpened?
>> 5. Can other materials, like silicon carbide, be used for sharpening tungsten carbide?
● Citations:
Tungsten carbide drill bits are renowned for their exceptional hardness and durability, making them ideal for drilling through hard materials like concrete and metal. However, even these robust tools eventually require sharpening to maintain their effectiveness. Sharpening tungsten carbide drill bits is a specialized process that demands the right tools and techniques. In this article, we will delve into the methods and materials needed to sharpen these drill bits effectively.
Introduction to Tungsten Carbide Drill Bits
Tungsten carbide is a composite material that combines tungsten and carbon, offering high hardness, wear resistance, and strength. These properties make tungsten carbide drill bits particularly useful for heavy-duty applications. However, their hardness also means they require specialized sharpening tools.
Characteristics of Tungsten Carbide Drill Bits
- Hardness and Durability: Tungsten carbide is one of the hardest materials used in drill bits, allowing it to withstand high friction and wear.
- High Wear Resistance: This property extends the lifespan of the drill bits, reducing the need for frequent sharpening or replacement.
- Corrosion Resistance: Tungsten carbide is resistant to corrosion, which helps maintain its performance over time.
A 5.5mm tungsten carbide drill bit, showcasing its compact size and robust construction.
Sharpening Tungsten Carbide Drill Bits
Sharpening tungsten carbide drill bits requires precision and the right equipment. The process typically involves using diamond-coated tools due to the material's extreme hardness.
Tools Needed for Sharpening
1. Diamond-Coated Grinding Wheels: These are essential for sharpening tungsten carbide due to their ability to effectively grind the material without causing damage.
2. Diamond Laps: Used for fine-tuning and polishing the cutting edges after initial sharpening with a diamond wheel.
3. Automatic Grinders or Bench Grinders: These machines provide the necessary speed and control for precise sharpening.
A diamond-coated grinding wheel, ideal for sharpening tungsten carbide drill bits.
Steps to Sharpen Tungsten Carbide Drill Bits
1. Assess the Drill Bit: Check for wear by examining the shine and feel of the cutting edges. A dull bit may still feel sharp due to its hardness.
2. Prepare the Sharpening Equipment: Ensure the diamond wheel is securely attached to the grinder and that the machine is set to the appropriate speed.
3. Sharpen the Drill Bit:
- Hold the drill bit at the correct angle (typically around 59 degrees for standard twist bits).
- Make light passes across the diamond wheel, removing minimal material each time.
- Use a diamond lap to finish and polish the cutting edges.
Challenges and Considerations
Sharpening tungsten carbide drill bits can be challenging due to the material's hardness and the cost of diamond-coated tools. Additionally, improper sharpening can damage the drill bit, reducing its effectiveness or rendering it unusable.
Cost and Accessibility of Diamond Tools
- Cost: Diamond-coated tools are more expensive than other sharpening materials, making them a significant investment for occasional use.
- Accessibility: While diamond tools are available, they may not be as widely accessible as other sharpening options, especially for hobbyists or small workshops.
Professional Sharpening Services
For those without access to diamond-coated tools or the expertise to sharpen tungsten carbide drill bits effectively, professional sharpening services can restore the drill bits to like-new condition.
A professional sharpening service, offering precise sharpening for tungsten carbide tools.
Alternative Sharpening Methods
While diamond-coated tools are the most effective for sharpening tungsten carbide, other methods and materials can be used in specific situations.
Silicon Carbide Wheels
Silicon carbide wheels are a more affordable alternative to diamond wheels. They can be used for rough sharpening or when diamond tools are not available. However, they wear down faster and may not achieve the same level of sharpness as diamond wheels[1][6].
Electrical Discharge Machining (EDM)
EDM is an advanced technique that uses electrical discharges to erode material from the surface of the drill bit. This method is highly precise and can be used for complex geometries without applying mechanical stress[1].
Laser Sharpening
Laser sharpening uses a focused laser beam to vaporize small amounts of material, restoring the sharpness of the drill bit. This method is non-contact and highly accurate, making it suitable for high-production environments[1].
Sharpening Angles and Geometry
Understanding the correct sharpening angles is crucial for maintaining the effectiveness of the drill bit.
Point Angle and Lip Relief Angle
- Point Angle: For standard twist bits, a 118-degree point angle is common, with each cutting lip ground at 59 degrees to the bit's axis. For harder materials, a 135-degree angle may be used[2].
- Lip Relief Angle: Typically between 8-12 degrees, this angle determines how effectively the bit penetrates the material. Too little relief can cause friction, while too much weakens the cutting edge[2].
Cryogenic Treatment for Extended Lifespan
Cryogenic treatment can enhance the durability of tungsten carbide drill bits by altering their microstructure, making them harder and more resistant to wear. This process can significantly extend the lifespan of the drill bits, reducing the need for frequent sharpening[8].
Conclusion
Sharpening tungsten carbide drill bits is a specialized process that requires diamond-coated tools and precise techniques. While it can be challenging and costly, maintaining these drill bits extends their lifespan and ensures optimal performance in demanding applications.
FAQ
1. What is the best tool for sharpening tungsten carbide drill bits?
The best tool for sharpening tungsten carbide drill bits is a diamond-coated grinding wheel. Diamond is the only material hard enough to effectively grind tungsten carbide without causing damage.
2. Can I sharpen tungsten carbide drill bits myself, or should I hire a professional?
While it is possible to sharpen tungsten carbide drill bits yourself, it requires specialized tools and expertise. If you lack experience or access to diamond-coated tools, hiring a professional may be more cost-effective.
3. What are the key angles for sharpening standard twist drill bits?
For standard twist drill bits, a point angle of 118 degrees (59 degrees per lip) and a lip relief angle of 8-12 degrees are typical.
4. How often should tungsten carbide drill bits be sharpened?
Tungsten carbide drill bits should be sharpened when they show signs of wear, such as reduced performance or visible dulling. This can vary depending on usage but typically occurs after drilling a significant number of holes.
5. Can other materials, like silicon carbide, be used for sharpening tungsten carbide?
While silicon carbide can be used for sharpening tungsten carbide, it is not as effective as diamond. Silicon carbide wheels are more affordable but wear down faster and may not achieve the same level of sharpness as diamond wheels.
Citations:
[1] https://passionblade.com/what-is-the-best-way-to-sharpen-tungsten-carbide-blade/
[2] https://onevantool.com/blogs/news/how-to-sharpen-drill-bits-with-an-angle-grinder-a-step-by-step-guide
[3] https://www.linkedin.com/pulse/how-sharpen-tungsten-carbide-shijin-lei
[4] https://www.hit-tw.com/newsdetails.aspx?nid=298
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[7] https://www.practicalmachinist.com/forum/threads/grinding-wheel-choices-for-sharpening-bits-hss-or-carbide.268465/
[8] https://ctpcryogenics.com/carbide-drill-bits/
[9] https://sawmillcreek.org/showthread.php?197445-CBN-wheel-sharpen-Tungsten-carbide-cutter
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[12] https://www.youtube.com/watch?v=9V7t_uy9QY8
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[29] https://www.drillbitwarehouse.com/tips-for-properly-sharpening-dull-drill-bits/
[30] https://www.youtube.com/watch?v=P3Gs09JdbjY
[31] https://www.youtube.com/watch?v=SzX1yEH6Cuo
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[36] https://www.hdtools.com.tw/tungsten-steel-drill-bit-series.html
