What’s the Best Way to Sharpen Drill Bits?
A sharp drill bit is one of the most underrated advantages in any workshop. This guide covers every sharpening method — from freehand grinding to dedicated machines — so you can pick the right approach for your skill level, budget, and workflow.
Ask ten experienced machinists how to sharpen a drill bit and you will get twelve different opinions. Some swear by freehand grinding mastered over decades. Others would not run a single bit without a dedicated electric sharpener. A few insist the bench grinder is all you ever need, while others point to bench stones, diamond files, and angle grinder attachments as perfectly valid alternatives.
The truth is there is no single universally “best” method. The best way to sharpen drill bits depends on what you are working with, how often you drill, what materials you cut, and how much precision your work demands. A hobbyist who drills wood twice a month has completely different needs from a metal fabricator who goes through a dozen bits per week.
This guide cuts through the noise. We will cover every practical sharpening method available today, explain the geometry that makes a drill bit work, show you how to recognize a dull bit before it damages your work, and help you choose the right approach for your specific situation.
1. Why Sharpening Drill Bits Matters
Most people replace drill bits when they stop cutting well. They grab a new bit, feel the difference immediately, and toss the old one in a drawer — or the bin. This is an expensive habit that most workshops do not need to maintain.
A properly sharpened drill bit cuts faster, generates less heat, requires less pressure from the user, and produces cleaner holes with better dimensional accuracy. A dull bit does the opposite on every count: it burns the material it is drilling through, generates enough friction heat to alter the temper of the bit itself (permanently reducing its hardness), causes the drill motor to work harder, and increases the risk of the bit binding, catching, or breaking.
The economics are straightforward. A set of quality cobalt drill bits can cost $40 to $150 depending on size range. A decent dedicated sharpener costs $80 to $200 and can sharpen those bits dozens of times over. Over any reasonable workshop lifetime, sharpening pays for itself many times over — and gives you a sharper bit than most new replacements from the mid-price tier.
2. How to Tell When a Drill Bit Is Dull
Dull bits rarely announce themselves with a sudden failure. They degrade gradually, and many users adapt to the worsening performance without noticing. Here are the definitive signs that a bit needs sharpening:
- Requires noticeably more pressure to start and continue drilling than before
- Produces fine dust instead of chips — a sharp bit lifts clean spiral chips; a dull bit grinds
- Bit or workpiece gets unusually hot during a standard drilling operation
- Squealing or squeaking sound rather than a clean cutting sound
- Hole edges are ragged or torn rather than clean and defined
- Bit wanders or “walks” on the surface before engaging the material
- Visible sheen or rounding on the cutting lips when examined under light
- The fingernail test fails — a sharp bit grips your nail; a dull one slides across it
The fingernail test is the quickest field check: press the bit’s cutting edge lightly across your thumbnail at roughly a 45° angle. A sharp bit immediately catches and bites into the nail surface. A dull bit slides without gripping. This works because the hardened nail surface behaves similarly to the initial engagement on a workpiece — the sharpness needed to cut metal is the same sharpness that grips the nail.
3. Understanding Drill Bit Geometry
Effective sharpening is impossible without understanding the geometry you are trying to restore. A standard twist drill bit has three critical geometric elements that must be maintained:
Point Angle
The point angle is the included angle at the very tip of the bit, measured between the two cutting lips. The most common standard is 118° for general-purpose HSS bits used on wood, plastic, and mild steel. Harder materials like stainless steel, cast iron, and hardened alloys benefit from a 135° point angle, which is less aggressive but stronger at the cutting edge. When sharpening, both lips must be ground to exactly the same angle — asymmetry is the most common sharpening error and causes the bit to drill oversized, off-center holes.
Lip Relief Angle (Clearance Angle)
Behind each cutting lip, the bit’s face slopes away from the cutting edge. This slope is the lip relief angle, typically between 8° and 15°. Too little relief and the bit rubs without cutting — essentially the same effect as a dull edge. Too much relief and the cutting edge becomes thin and fragile, chipping rapidly under load. This angle is automatically set by dedicated sharpeners but requires practiced judgment when grinding freehand.
Chisel Edge
At the absolute center of the bit’s tip is the chisel edge — a short, non-cutting web that connects the two lips. The chisel edge does not cut; it pushes and compresses material. A properly ground chisel edge is short and centered. A split-point grind eliminates the chisel edge entirely by creating additional cutting faces at the center, dramatically improving bit self-centering and reducing thrust required. This is why split-point bits cut so much more easily on metal than standard 118° plain-ground bits.
Helix Angle (Flute Geometry)
The spiral flutes are not ground during sharpening, but they affect how you hold and feed the bit. The flute’s job is chip evacuation — pulling cut material away from the cutting zone as the bit advances. Worn or clogged flutes significantly reduce cutting efficiency even on a perfectly sharpened tip. Keep flutes clean with a brush or compressed air and inspect them for deep gouges that might indicate the bit is past salvage.
4. The 6 Best Ways to Sharpen Drill Bits
Below we cover every practical method used in workshops today, from the entry-level to the professional. Each method includes an honest assessment of its skill requirements, the time investment needed, the results you can realistically expect, and who it is best suited for.
Method 1: Dedicated Electric Drill Bit Sharpener
Dedicated Electric Drill Bit Sharpener
✔ Best Overall MethodA purpose-built electric drill bit sharpener — whether a collet-based machine like the VEVOR MR-13A or a cam-guided design like the Drill Doctor DD750X — is the most reliable way to sharpen drill bits consistently and repeatably. These machines mechanically control the point angle, lip relief angle, and bit positioning so that operator technique plays a minimal role in the outcome.
Collet-based sharpeners (MR-13A type) hold the bit by its exact diameter using a matched collet, ensuring zero positioning error. The operator selects the point angle, loads the bit, and feeds it to the rotating CBN or diamond wheel. Results are highly consistent from the very first use, with minimal learning curve. Cam-guided sharpeners (Drill Doctor type) use a chuck and cam system that guides the bit through the correct arc during sharpening — slightly more skill-dependent but capable of handling a wider range of bit sizes and offering split-point creation.
- Skill required: Low to moderate
- Time per bit: 2–5 minutes
- Result quality: Excellent — near-factory geometry
- Cost: $80–$200 for the machine; bits sharpened for free indefinitely
- Best for: Regular users, workshops, anyone who values consistent results over technique
Method 2: Bench Grinder (Freehand)
Bench Grinder — Freehand Technique
Good — Requires PracticeThe bench grinder is the traditional sharpening tool for drill bits and remains the most common approach in production shops and professional environments where the operator has invested time in mastering the technique. Done correctly, freehand grinding on a bench grinder produces results comparable to a dedicated sharpener. Done incorrectly — and it frequently is, even by experienced users — it produces an asymmetric grind that is worse than a dull bit.
The technique requires holding the bit at the correct point angle (118° or 135°), applying the cutting lip flat to the face of the wheel, and simultaneously sweeping the bit downward while rotating it slightly — this combined motion creates the lip relief angle. The critical challenge is maintaining identical geometry on both lips, which requires feel and muscle memory that only develops through extensive practice.
Use a medium-grit aluminum oxide wheel (60–80 grit for removing metal, 120 grit for finishing). Keep a container of water nearby to cool the bit frequently — bench grinders generate significant heat and over-tempering the bit tip is a real risk. Check for symmetry frequently using a drill point gauge.
- Skill required: High — 20–30 practice bits before reliable results
- Time per bit: 3–10 minutes (longer early in the learning curve)
- Result quality: Excellent when mastered; poor when not
- Cost: Near-zero if you already own a bench grinder ($50–$150 if not)
- Best for: Experienced machinists, production shops, users willing to invest in the technique
- 1Position the bit at approximately 59° to the wheel face (half of the 118° included angle). Rest your index finger on the tool rest as a pivot.
- 2Apply the cutting lip flat to the wheel face, maintaining the 59° angle. The cutting edge should be parallel to the wheel surface at first contact.
- 3Simultaneously lower the shank and rotate the bit slightly clockwise (for right-hand bits). This combined motion creates the lip relief angle behind the cutting edge.
- 4Cool the bit in water every 3–4 seconds. Never let the tip become too hot to touch.
- 5Rotate 180° and repeat exactly for the second lip, using the same angles and pressure.
- 6Inspect with a drill point gauge or compare both lips visually under bright light. Both lips must be equal length, meeting at the exact center of the bit.
Method 3: Angle Grinder with Sharpening Attachment
Angle Grinder with Drill Bit Attachment
Versatile but LimitedDedicated angle grinder attachments for drill bit sharpening — often sold as low-cost accessories — clamp onto the angle grinder body and provide a guide fixture for holding bits at a set angle while the grinder’s disc does the grinding. They are a practical option for workshops that already own an angle grinder but do not want to invest in a dedicated sharpener.
The results are adequate for casual use on larger bits but lack the precision of a dedicated machine. Most attachments have limited angle adjustment, and the inherently aggressive nature of an angle grinder makes heat management more critical. These attachments work best on bits above 6mm where there is enough material to work with safely. Very small bits are difficult to control safely with this approach.
- Skill required: Moderate
- Time per bit: 3–7 minutes
- Result quality: Functional but not precision-grade
- Cost: $15–$40 for the attachment (angle grinder required)
- Best for: Field use, emergency sharpening, large bits only
Method 4: Drill-Powered Sharpening Attachment
Drill-Powered Sharpening Attachment
Budget Entry PointThese small cylindrical or conical attachments fit into the chuck of a standard corded or cordless drill and feature a pre-cut diamond-coated abrasive groove that the drill bit slides into at the correct angle. Popular examples include the Drill Doctor 100 and various generic “sharpen-in-seconds” accessories sold online and in hardware stores.
They are genuinely the easiest method to use — insert the bit into the groove, run the drill for 10–30 seconds, repeat on the second face — and produce acceptable results on standard 118° twist bits in soft-to-medium materials. However, they cannot adjust point angle, do not address lip relief accurately, and wear out relatively quickly. They are best thought of as a maintenance tool for slightly dull bits rather than a rescue tool for badly worn ones.
- Skill required: Very low
- Time per bit: 1–3 minutes
- Result quality: Acceptable for light maintenance; poor for damaged bits
- Cost: $15–$35
- Best for: Occasional home users, wood and plastic drilling, quick touch-ups
Method 5: Diamond File or Bench Stone
Diamond File or Bench Stone (Hand Sharpening)
Slowest — High SkillHand sharpening with a diamond file, diamond paddle, or fine-grit bench stone is the most traditional method and requires the most manual skill. A flat diamond file (typically 300–600 grit for HSS) is drawn across the cutting face of the bit while maintaining the correct angle by eye and feel alone. This approach gives the most control of any method — you can feel exactly what material is being removed and where — but translating that control into a consistent, geometrically accurate result takes considerable experience.
Hand sharpening is most practical for emergency field sharpening when no powered tools are available, for sharpening very small bits (under 3mm) that no powered sharpener can handle, and as a finishing stroke after grinding to produce the finest possible cutting edge on high-precision bits. For regular workshop use, it is too slow and skill-dependent to be the primary method.
- Skill required: Very high for accurate results
- Time per bit: 5–20 minutes
- Result quality: Excellent if skilled, poor if not
- Cost: $10–$30 for a good diamond file set
- Best for: Field emergency sharpening, tiny bits, finishing work, experienced craftspeople
Method 6: Dremel / Rotary Tool
Dremel / Rotary Tool with Grinding Bit
Emergency Use OnlyA Dremel or other rotary tool fitted with a small aluminum oxide or diamond grinding point can be used to touch up drill bits in the same way a diamond file can — except faster and with less physical effort. The technique involves carefully applying the spinning grinding bit to the cutting face of the drill bit, maintaining the correct angle by hand.
This method works reasonably well for touching up slightly dull bits and for sharpening very small bits where other methods cannot reach. The small grinding wheel diameter makes it practical for working on bits as small as 1.5mm, which is genuinely useful. The drawback is control — at 20,000+ RPM with a small grinding bit, material removal is aggressive and inconsistent pressure can easily remove too much from one area. Not recommended as a primary sharpening method for anything critical.
- Skill required: Moderate–High for accurate results
- Time per bit: 3–8 minutes
- Result quality: Variable — best for small bits and touch-ups
- Cost: $30–$80 for a Dremel; grinding bits $5–$15
- Best for: Very small bits, touch-up work, emergency field use
5. Method Comparison Table
| Method | Skill Needed | Speed | Precision | Cost | Best Bit Size |
|---|---|---|---|---|---|
| Dedicated Sharpener (Collet) | Low | Fast | Excellent | $$ | 3–13mm (metric) |
| Dedicated Sharpener (Cam-guided) | Moderate | Fast | Very Good | $$ | 3/32″–3/4″ |
| Bench Grinder (Freehand) | High | Moderate | Good (skilled) | $ (if owned) | All sizes |
| Angle Grinder Attachment | Moderate | Moderate | Adequate | $ | 6mm+ recommended |
| Drill-Powered Attachment | Very Low | Fast | Basic | $ | Standard twist only |
| Diamond File / Bench Stone | Very High | Slow | Good (skilled) | $ | All, incl. tiny bits |
| Dremel / Rotary Tool | Moderate–High | Moderate | Variable | $ | Small bits, touch-ups |
6. Point Angle Reference Guide
Choosing the right point angle for the material you are drilling is just as important as the sharpness of the cutting edge. Here is a practical reference for the most common drilling applications:
| Point Angle | Material / Application | Notes |
|---|---|---|
| 90° – 100° | Soft plastics, copper, soft aluminium | Very aggressive; prevents the bit from grabbing in soft material |
| 118° | General-purpose: wood, plastics, mild steel, aluminium | The universal standard for most HSS twist bits; balanced between aggression and strength |
| 130° – 135° | Hardened steel, stainless steel, cast iron, titanium | Stronger cutting edge for hard materials; reduces chipping and chatter |
| 140° | Very hard alloys, fiberglass, composites | Maximum edge strength for abrasive or extremely hard materials |
| Split Point (any angle) | Metal drilling without center punch | Eliminates chisel edge; self-centering; dramatically reduces thrust and walking |
| 60° – 90° | Masonry / SDS bits (special) | Masonry bits have carbide inserts — sharpened only with diamond/SDC tools |
7. Best Sharpening Approach by Bit Material
High-Speed Steel (HSS) Bits
The most common type. HSS bits are sharpened with aluminum oxide wheels (bench grinder), diamond wheels (Drill Doctor), or CBN wheels (VEVOR MR-13A). CBN is the premium choice for HSS — it produces the finest edge finish and generates the least heat during grinding. All six methods described above work on HSS bits.
Cobalt Bits (M35, M42)
Cobalt bits are HSS with cobalt alloyed into the steel throughout — not as a surface coating. This means the cobalt remains present after sharpening, and the bit retains its cobalt-grade hardness and heat resistance at the newly sharpened tip. Cobalt bits are sharpened with the same methods as HSS but are particularly worth sharpening because of their higher replacement cost. The ROI on sharpening cobalt bits is excellent.
TiN / TiAlN Coated Bits
Titanium nitride and similar coatings are surface treatments applied to HSS bits. Sharpening removes the coating from the newly ground tip faces, but the underlying HSS steel is fully functional and the bit cuts normally. The anti-friction and anti-corrosion benefits of the coating are lost at the tip but retained on the flute surfaces, which still provide most of the coating’s benefit during actual drilling.
Carbide (Solid Carbide / Carbide-Tipped) Bits
Carbide is far harder than HSS and requires a diamond (SDC) wheel for grinding. Standard aluminum oxide or CBN wheels will not effectively sharpen carbide and may glaze or crack. The VEVOR MR-13B with its included SDC wheel handles carbide-tipped masonry and metal bits. Solid carbide bits are typically sent to specialist grinding services rather than sharpened in-workshop due to the precision required for their geometry.
Black Oxide Bits
Black oxide is a rust-resistant surface treatment — not a hardness coating. These are standard HSS bits with a dark finish. Sharpening removes the black oxide from the tip but the bit performs identically to bare HSS. All standard sharpening methods apply.
8. Common Sharpening Mistakes to Avoid
- Asymmetric lips: The most common error. Both cutting lips must be the same length and ground at identical angles. An asymmetric grind causes the bit to cut oversize holes and walk off-center. Always inspect with a drill point gauge or bright light after sharpening.
- Overheating the tip: Grinding too aggressively without cooling generates heat that destroys the temper of HSS steel. The tip turns straw-yellow, then blue — visible proof of permanent damage. Cool the bit in water every few seconds during bench grinding. Dedicated sharpeners typically remove material slowly enough to avoid this problem.
- Insufficient lip relief: Grinding only the cutting edge without creating adequate relief behind it produces a bit that rubs rather than cuts. The face behind each cutting lip must slope away — without this clearance, the full flat face behind the edge contacts the material and friction prevents cutting.
- Wrong angle for the material: Sharpening a 118° bit to 135° to use on soft wood is not harmful, but the reverse — using a 118° bit on hardened steel — will chip the edges rapidly. Match your sharpened angle to your most demanding use case.
- Sharpening the wrong bits: Bits smaller than 3mm are generally not worth sharpening with power equipment — hand files or a Dremel are safer. Completely snapped bits with significant length missing may no longer fit securely in a chuck after resharpening to the break point. Know when to replace rather than restore.
- Ignoring the chisel edge: Some sharpeners and freehand grinders focus only on the cutting lips and leave a wide, blunt chisel edge at the center. A wide chisel edge requires enormous thrust to start drilling and causes wandering. A properly sharpened bit has a very short, centered chisel edge — or a split-point grind that eliminates it entirely.
9. Frequently Asked Questions
Q: Can I sharpen drill bits without a machine?
Yes. A bench grinder, diamond file, or Dremel can sharpen drill bits without a dedicated sharpening machine. However, all of these methods require practice and technique to produce good results. For occasional use where absolute precision is not critical, a drill-powered sharpening attachment is the simplest no-machine option. For precision results without skill dependency, a dedicated electric sharpener is the better long-term investment.
Q: How many times can you sharpen a drill bit before it’s useless?
A standard twist bit can typically be sharpened 8–15 times before it becomes too short to grip securely in a chuck. Using conservative material removal each time — sharpening as soon as the bit dulls rather than waiting for complete failure — maximizes the number of sharpenings per bit. Very small bits (under 4mm) may yield only 3–5 sharpenings due to their limited overall length.
Q: Is it worth sharpening cheap drill bits?
Cheap HSS bits are worth sharpening once or twice — the steel is softer than premium bits but still cuttable and functional when sharp. However, cheap bits often have softer steel that dulls faster between sharpenings, and the economics of repeatedly sharpening them diminish quickly. If you sharpen regularly, investing in a good set of cobalt bits and maintaining them well will serve you better than a revolving stock of cheap bits.
Q: Can you sharpen masonry drill bits?
Yes, but only with diamond (SDC) abrasive tools — standard grinding wheels will not cut carbide effectively. Carbide-tipped masonry bits can be touched up with a diamond dresser or flat diamond file on the carbide tip face. A VEVOR MR-13B or similar machine with an SDC wheel handles this properly. Masonry bits that have completely lost their carbide inserts are not restorable and should be replaced.
Q: What’s the difference between a 118° and 135° drill bit point?
A 118° point is more acute (sharper-looking) and more aggressive — it starts cutting quickly with less applied pressure. It is ideal for wood, plastic, and soft metals. A 135° point has a flatter, more obtuse profile that creates a stronger, wider cutting edge. It is preferred for hardened steel, stainless, and difficult alloys where the cutting edge needs to resist chipping under high load. Split-point bits at either angle add self-centering capability by eliminating the non-cutting chisel edge at the tip center.
Q: Do sharpened bits perform as well as new ones?
A correctly sharpened quality bit (cobalt, premium HSS) performs at least as well as a new mid-range bit and in many cases better, since the original bit was manufactured to tighter tolerances than budget replacements. The key word is “correctly” — a poorly sharpened bit with asymmetric lips or incorrect relief angle performs worse than a dull bit. This is why dedicated sharpeners that mechanically control geometry consistently outperform freehand methods for most users.
Q: What angle should I hold a drill bit on a bench grinder?
For a standard 118° bit, hold the cutting lip at approximately 59° to the face of the grinding wheel (half the included angle). The cutting edge should be roughly parallel to the wheel face at initial contact. As you apply the bit to the wheel, simultaneously lower the shank end about 10–15° while rotating the bit slightly. This combined motion — practiced until it becomes a single fluid movement — creates the correct lip relief angle behind the cutting edge.
What’s the Best Way to Sharpen Drill Bits?
For most workshop users — whether you are a serious DIYer, a general contractor, a woodworker, or a metalworker — a dedicated electric drill bit sharpener is the best answer. It requires no mastery of freehand technique, produces consistently excellent results from the first use, and pays for itself rapidly against the cost of replacement bits. For metric HSS users, the collet-based VEVOR MR-13A is the most precise and user-friendly option. For imperial-size bit collections or split-point capability, the cam-guided Drill Doctor DD750X fills the gap.
If you already own a bench grinder and are willing to invest 20–30 practice bits in developing the technique, freehand grinding is a completely viable path that costs virtually nothing and produces excellent results once mastered. It is the preferred method in production environments precisely because skilled operators can produce consistent results quickly without any machine overhead.
For emergency or occasional use — touching up a slightly dull bit on-site without a dedicated machine — a drill-powered sharpening attachment or diamond file is entirely adequate. Just do not mistake occasional adequacy for consistent excellence: if drill bits are an important part of your work, invest in a proper sharpening solution. Your bits will last longer, your holes will be cleaner, your motors will run cooler, and every drilling task will take less effort. Few workshop upgrades deliver a better return on investment.