How To Sharpen Drill Bits With Angle Grinder: A Quick Guide

Yes, you can sharpen drill bits with an angle grinder, but it requires skill and caution. This guide provides a step-by-step approach to safely and effectively sharpening drill bits with a grinder, even covering the use of a drill bit sharpening jig or DIY drill bit sharpener. We’ll explore various drill bit sharpening techniques and angle grinder sharpening methods, weighing the pros and cons of sharpening drill bits freehand versus using a jig. Finally, we’ll touch on aspects of metalworking drill sharpening and provide a comprehensive angle grinder drill sharpening guide.

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The Basics of Drill Bit Sharpening

A dull drill bit makes hard work of any project. It can cause the drill to wander, create rough holes, and even overheat the bit and damage your workpiece. Knowing how to properly sharpen your drill bits can save you money and improve your results. This guide will help you achieve a sharp and efficient drill bit using an angle grinder.

Why Sharpen Drill Bits?

• Improved Performance: Sharp bits cut faster and cleaner.
• Reduced Effort: Sharp bits require less force to drill, reducing strain on you and your drill.
• Extended Bit Life: Sharpening prevents excessive wear and tear, prolonging the life of your drill bits.
• Cost Savings: Sharpening eliminates the need to constantly replace dull bits.
• Safety: Sharp bits are less likely to slip or bind, reducing the risk of injury.

Preparing for Drill Bit Sharpening

Before you start grinding, gathering the right equipment and taking necessary safety precautions is very important.

Essential Tools and Materials

• Angle Grinder: Choose an angle grinder with a fine-grit grinding wheel suitable for sharpening metal.
• Safety Glasses: Always wear safety glasses to protect your eyes from flying sparks and debris.
• Gloves: Wear work gloves to protect your hands from heat and sharp edges.
• Dust Mask or Respirator: Grinding metal creates dust particles that can be harmful to breathe.
• Water or Coolant: To keep the bit cool during sharpening, prevent overheating and metal damage.
• Bench Vise (Optional): To hold the bit steady, a bench vise is highly recommended.
• Drill Bit Sharpening Jig (Optional): A jig can help you maintain the correct angle and consistency.
• Lighting: Good lighting is essential for clear visibility.

Safety First: Precautions

• Read the Manuals: Carefully read and understand the operating manuals for both your angle grinder and any sharpening jig you may be using.
• Inspect Equipment: Check your angle grinder and grinding wheel for any signs of damage before each use.
• Secure the Workpiece: If using a vise, ensure the drill bit is securely clamped.
• Ventilation: Work in a well-ventilated area to avoid inhaling dust particles.
• Avoid Loose Clothing: Wear close-fitting clothing and tie back long hair to prevent them from getting caught in the grinder.
• Practice: Before sharpening valuable drill bits, practice on scrap metal or old, dull bits.

Sharpening Drill Bits Freehand with an Angle Grinder

Sharpening drill bits freehand requires practice and a steady hand. Here’s how to approach it:

Step-by-Step Guide to Freehand Sharpening

1. Secure the Drill Bit: Hold the drill bit firmly with gloves, or clamp it in a vise, exposing the cutting edge.
2. Identify the Cutting Angle: Observe the original angle of the cutting edge. Aim to replicate this angle during sharpening (typically 59 degrees for general-purpose bits).
3. Initial Grinding: Gently touch the cutting edge to the grinding wheel at the correct angle. Use light pressure and short bursts to avoid overheating. Focus on removing any visible damage or dullness.
4. The Lip Relief Angle: After shaping the cutting edge, you must create the lip relief angle (the clearance behind the cutting edge). Tilt the bit slightly downwards as you touch it to the grinding wheel, gently grinding away a small amount of metal behind the cutting edge.
5. Sharpening the Second Flute: Repeat steps 3 and 4 for the second flute, ensuring that both flutes are sharpened equally. Symmetry is crucial for proper drilling.
6. Cooling: Frequently dip the drill bit in water or coolant to prevent overheating.
7. Inspection: After sharpening, examine the bit closely. The cutting edges should be sharp, symmetrical, and free of burrs.
8. Deburring (Optional): Use a honing stone or a fine file to remove any burrs from the cutting edges.

Tips for Freehand Sharpening

• Maintain a Steady Hand: A steady hand is crucial for achieving consistent results.
• Use Light Pressure: Avoid applying too much pressure, which can overheat the bit and damage the grinding wheel.
• Keep the Bit Moving: Continuously move the bit across the grinding wheel to prevent localized overheating.
• Practice Makes Perfect: Freehand sharpening takes practice. Don’t be discouraged if your first attempts aren’t perfect.
• Check Frequently: Keep checking the bit’s edge to ensure you are not removing too much material.

Pros and Cons of Freehand Sharpening

Feature	Pros	Cons
Cost	No additional equipment needed.	Requires practice and skill to achieve consistent results.
Speed	Can be faster once mastered.	Difficult to maintain the correct angles.
Versatility	Can be used on various drill bit sizes and types.	Increased risk of overheating and damaging the bit.
Consistency	N/A	More challenging to achieve symmetrical and accurate sharpening.

Using a Drill Bit Sharpening Jig with an Angle Grinder

Using a drill bit sharpening jig can greatly simplify the process and improve accuracy. An angle grinder drill sharpener jig holds the drill bit at the correct angle, making it easier to achieve consistent results. A DIY drill bit sharpener jig can also be made at home.

Selecting a Drill Bit Sharpening Jig

• Compatibility: Ensure the jig is compatible with your angle grinder and the range of drill bit sizes you need to sharpen.
• Adjustability: Look for a jig that allows you to adjust the sharpening angle.
• Durability: Choose a jig made from sturdy materials that can withstand repeated use.
• Ease of Use: Opt for a jig with clear instructions and a simple design.

Step-by-Step Guide to Using a Sharpening Jig

1. Mount the Jig: Attach the sharpening jig to your angle grinder according to the manufacturer’s instructions.
2. Adjust the Angle: Set the jig to the desired sharpening angle (typically 59 degrees for general-purpose bits).
3. Secure the Drill Bit: Insert the drill bit into the jig and tighten the clamp.
4. Grind the Cutting Edge: Turn on the angle grinder and gently move the jig across the grinding wheel, applying light pressure.
5. Sharpening the Second Flute: Rotate the drill bit in the jig to sharpen the second flute, ensuring that both flutes are sharpened equally.
6. Cooling: Frequently dip the drill bit in water or coolant to prevent overheating.
7. Inspection: After sharpening, examine the bit closely. The cutting edges should be sharp, symmetrical, and free of burrs.
8. Deburring (Optional): Use a honing stone or a fine file to remove any burrs from the cutting edges.

Pros and Cons of Using a Sharpening Jig

Feature	Pros	Cons
Accuracy	Helps maintain consistent angles, leading to more accurate sharpening.	Requires purchasing a sharpening jig.
Ease of Use	Simplifies the sharpening process, making it easier for beginners.	May not be compatible with all drill bit sizes and types.
Consistency	Ensures that both flutes are sharpened equally.	Can be slower than freehand sharpening once mastered.
Repeatability	Makes it easy to replicate the same sharpening results on multiple bits.	Initial setup and adjustment can be time-consuming.

Advanced Drill Bit Sharpening Techniques

Beyond the basic sharpening process, mastering these advanced techniques can improve the performance and lifespan of your drill bits.

Split Point Sharpening

Split point drill bits have a chisel-shaped point that helps to center the bit and prevent wandering. To sharpen a split point bit:

1. Grind the Primary Cutting Edges: Sharpen the primary cutting edges as described in the previous sections.
2. Create the Split Point: Use a small grinding wheel or a rotary tool with a grinding attachment to carefully grind a small notch in the center of the drill bit tip, creating the split point.
3. Deburr: Remove any burrs from the split point using a honing stone or a fine file.

Sharpening Different Types of Drill Bits

• Twist Drill Bits: The most common type, sharpened as described in the previous sections.
• Spade Bits: Sharpen the cutting edges of the spade, maintaining the original angle.
• Step Bits: Sharpen each step individually, maintaining the original angle and diameter.
• Masonry Bits: These bits have a carbide tip. Use a diamond grinding wheel to sharpen the carbide tip.

Optimizing Drill Bit Geometry

• Point Angle: The point angle is the angle between the two cutting edges. A 118-degree point angle is suitable for general-purpose drilling, while a 135-degree point angle is better for drilling harder materials.
• Lip Relief Angle: The lip relief angle is the angle behind the cutting edge. A proper lip relief angle ensures that the cutting edge is the only part of the bit that contacts the workpiece.
• Chisel Edge Angle: The chisel edge angle is the angle of the chisel edge in the center of the drill bit. A smaller chisel edge angle reduces the amount of force required to start the drill bit.

Common Mistakes to Avoid

• Overheating: Overheating can soften the metal and ruin the drill bit. Use coolant and avoid applying too much pressure.
• Uneven Sharpening: Uneven sharpening can cause the drill bit to wander and create oversized holes.
• Incorrect Angle: Using the wrong sharpening angle can reduce the bit’s cutting efficiency.
• Removing Too Much Material: Removing too much material can weaken the drill bit and shorten its lifespan.
• Ignoring Safety Precautions: Always wear safety glasses, gloves, and a dust mask to protect yourself from injury.

FAQ – Sharpening Drill Bits

Here are some frequently asked questions about sharpening drill bits with an angle grinder:

Can I use any angle grinder to sharpen drill bits?
Yes, you can use most angle grinders, but you’ll want a fine-grit grinding wheel. Also, smaller angle grinders are often easier to control for this task.

What is the best grinding wheel for sharpening drill bits?
The best grinding wheel for sharpening drill bits is a fine-grit aluminum oxide wheel. These wheels are designed for sharpening metal and produce a smooth, clean edge.

How do I know if my drill bit is sharp enough?
A sharp drill bit will cut smoothly and easily through the material. If the bit is dull, it will require more force to drill, and it may produce rough or oversized holes.

How often should I sharpen my drill bits?
Sharpen your drill bits whenever they become dull or show signs of wear. The frequency of sharpening depends on the type of material you are drilling and the amount of use the bits receive.

Is it better to sharpen drill bits or buy new ones?
Sharpening drill bits is more cost-effective than buying new ones, especially if you have a lot of bits to maintain. However, if a drill bit is severely damaged or broken, it may be more economical to replace it.

Conclusion

Sharpening drill bits with an angle grinder is a valuable skill for any metalworker. Whether you choose to sharpen drill bits freehand or use a drill bit sharpening jig, understanding the drill bit sharpening techniques and following safety precautions will help you achieve sharp, efficient, and long-lasting drill bits. By mastering these angle grinder sharpening methods, you’ll be able to save money and improve the quality of your work. This angle grinder drill sharpening guide provides a solid foundation for your metalworking drill sharpening endeavors.