How to Sharpen Drill Bits: 7 Simple Steps

Buying good tools is only half the job. Keeping them in shape is the other half, and drill bits need that upkeep more than most.

Every bit dulls with use. Brick, hardwood, and metals wear down the cutting edge after a few hundred holes, whether you run a jobsite or a weekend workshop.

This guide walks through how to sharpen drill bits on a bench grinder in seven steps, which tool fits your setup, and how to set the right point angle so the edge actually bites. A fresh edge costs a few minutes and saves the price of a new set.

Why You Should Sharpen Your Drill Bits

If you want clean holes with minimal effort, you must dedicate time to sharpening your tools.

Sharpening is a core part of toolkit maintenance. Replacing dull drill bits gets expensive quickly, so it makes sense to extend their lifespan. Safety matters too, because a blunt bit needs more force, and more force means a higher chance of the bit slipping and causing injury.

On a practical level, a sharp bit works faster. Dull edges slow you down, so the few minutes it takes to grind a fresh edge is a solid investment of your time.

Signs Your Drill Bit Is Dull

When a sharp bit spins, you feel it bite into the material immediately. It makes a clean cutting sound and ejects uniform chips or spirals of debris.

A dull bit behaves differently:

• Excessive heat: The bit generates friction rather than cutting, leading to smoke or a burning smell.
• Squealing noise: You hear a high-pitched screeching sound as the metal rubs against the material.
• Slow progress: You have to lean hard on the drill to make a dent.
• Fine dust: Instead of chips, the drill produces fine powder (especially in wood).

If you see smoke, stop immediately. Pushing a dull bit can ruin the material, damage your drill motor, or start a fire.

Best Tools for Sharpening Drill Bits

Bench Grinder

For those with a steady hand, a bench grinder is the classic method for restoring a cutting edge.

Bench grinders are versatile and powerful. You put on eye protection, fire up the wheel, and grind the bit freehand. A 60 to 80 grit aluminum oxide wheel cuts high-speed steel without building up too much heat. The method works well, but it takes practice to hold the correct tip angle and keep both sides symmetrical.

You can use a grinder for twist bits, masonry bits, and spur point bits. One caveat for masonry bits: their tungsten carbide tip barely responds to the aluminum oxide wheel that cuts steel bits, so you need a green silicon carbide wheel to touch up that hard tip. Most units feature coarse and fine wheels; start with the coarse to shape the bit and finish with the fine wheel for a smooth edge.

Drill Doctor

If you want factory-level precision without the learning curve of a grinder, this dedicated tool is the industry standard.

A drill bit sharpening tool like the Drill Doctor is a favorite among professionals. While the upfront cost is higher, it pays for itself by saving piles of dull bits from the trash can. It excels at sharpening twist and masonry bits.

The system uses a chuck to clamp the bit at the exact correct angle. You insert the chuck into the sharpening port and rotate it. The machine grinds the relief and cutting angles simultaneously, removing human error from the equation.

Most users find that 20 to 40 half-turns are enough to restore a razor-sharp edge.

Diamond File

A diamond file offers ultimate control for delicate bits or field sharpening where electricity isn’t available.

This manual method is slower but allows for high precision. It is often the only way to sharpen auger bits, pilot screws, and countersink bits that won’t fit in a grinder. The tapered shape helps you reach into tight cutting flutes.

Since diamond files don’t have directional teeth like steel files, you can scrub back and forth. Use firm, even strokes to hone the edge.

Drill-Powered Bit Sharpening Tool

This budget-friendly attachment utilizes the power of your existing hand drill to grind edges quickly.

These attachments are a great middle-ground for DIYers who don’t want to buy a bench grinder. They attach to the collar of your drill and spin a small internal grinding stone.

You insert the dull bit into the appropriate guide slot and let the stone do the work. While it lacks the micrometer precision of the Drill Doctor, it is usually sufficient for general wood and soft metal drilling tasks.

Dremel Tool

A Dremel or rotary tool acts as a miniature handheld grinder, perfect for touching up smaller drill bits.

You can use a Dremel to sharpen twist, flat wood, and masonry bits. The advantage here is visibility; you can see exactly where the stone meets the metal. For best results, clamp the Dremel to a workbench or use a specialized sharpening attachment that screws onto the rotary tool housing.

How to Sharpen Drill Bits With a Bench Grinder

Sharpening by hand is a valuable skill. Follow these steps to restore your bits safely and effectively.

What You Need

• Bench grinder: A 60 to 80 grit aluminum oxide wheel cuts high-speed steel without overheating it, and a finer wheel gives a cleaner finish pass. A belt sander is a decent alternative.
• Safety gear: Goggles are mandatory. Sparks and metal shavings will fly.
• Water container: Essential for cooling the steel to preserve its temper.
• Scrap wood: For testing your results immediately.
• Gloves (Caution): Do not wear loose gloves near spinning machinery. Tight-fitting mechanics gloves or bare hands are safer to prevent snagging.

1. Inspect Your Bits

Sort your collection. If a bit is severely chipped, bent, or burnt blue, it might be past the point of rescue. Focus on bits that are simply dull from normal wear.

2. Understand the Angle

For a standard general-purpose twist bit, aim for a point angle of 118 degrees. When you hold the bit against the grinding wheel, the shaft should sit at roughly 60 degrees relative to the face of the wheel, since the two cutting lips together form the 118-degree point.

That 118-degree angle is the all-purpose choice and cuts well in wood, plastic, and soft metals up to aluminum. If you mostly drill hard materials like stainless steel or cast iron, grind a flatter 135-degree point instead. It is self-centering, so it starts without walking, and it holds up far longer in hard metal, where a sharp 118-degree point wears out fast.

3. The Grinding Technique

Turn on the grinder and hold the bit securely with both hands. Place the cutting face (the land) against the wheel.

As the metal touches the wheel, use a smooth sweeping motion. Push slightly forward and lift the shank (the tail end) of the bit upward. That motion grinds a small clearance behind the cutting edge, called the lip relief angle, which lets the bit clear material as it spins. Aim for roughly 8 to 12 degrees of relief for general work. Too much relief leaves the edge unsupported and it chips, while too little makes the edge rub instead of cut.

Do not rotate the bit like you are drilling. Move it in a steady sweeping arc.

4. Keep It Cool

Grinding builds heat fast, and heat is what ruins a bit. If the steel gets too hot, it loses its hardness and won’t hold an edge. Watch the color of the tip as you work. A light straw-yellow tint is fine, but a blue or purple color means you have cooked the temper out of that section for good, and it will never take an edge again. Dip the tip into your water container every 5 to 10 seconds and let it sit for a moment before you return to the wheel. If a spot has already turned blue, grind past it to reach sound metal.

5. Balance the Sides

A drill bit has two cutting lips. You must grind both equally. If one side is longer than the other, the bit will wobble and drill an oversized hole.

Count your seconds or strokes. If you grind the left side for three seconds, do the same for the right. Aim for the point to be perfectly centered.

Color the cutting edges with a felt-tip marker before you grind. After a light pass, the bare metal shows exactly where the wheel removed steel, so you can see at a glance whether both lips are wearing down evenly.

6. Test for Sharpness

Once the edges look clean and shiny, push the tip (by hand) into a piece of scrap wood. A sharp bit will snag and bite into the wood with a slight turn. If it slides around, it is still dull.

7. The Final Drill Test

Load the bit into your drill and bore a hole in scrap material. It should cut smoothly without you needing to lean your body weight on the tool. If it cuts fast and ejects chips, you are done.

Tips to Maintain Drill Bit Sharpness

Tip #1: Match the Bit to the Material

Using a wood bit on masonry will destroy it instantly. Likewise, using a standard steel bit on hardened steel will flatten the cutting edge in seconds. Always check the packaging to ensure your bit is rated for the material you are drilling.

Tip #2: Control Your Speed

Speed kills drill bits. Drilling too fast generates excess heat. Harder materials (like steel) require slower drilling speeds, while softer materials (like pine) can handle higher speeds.

Tip #3: Clear the Debris

Don’t force the bit through deep holes in one go. Use a “pecking” motion: drill down an inch, pull the bit up to eject dust/chips, and plunge back in. This prevents the flutes from clogging and reduces heat buildup.

Tip #4: Lubricate While Drilling

When drilling metal, always use cutting oil or lubricant. This reduces friction, keeps the bit cool, and significantly extends the life of the cutting edge.

Tip #5: Proper Storage

Tossing bits loose into a toolbox damages the cutting edges as they rattle against other tools. Keep them in an index case or a rack. Store them in a dry place to prevent rust corrosion.

FAQs

How Many Degrees Should the Clearance Angle Be Ground To?

Grind the lip clearance behind each cutting edge to about 8 to 12 degrees for general-purpose drilling, and closer to 6 to 8 degrees for harder materials that need more edge support. The point angle is a separate measurement. Use 118 degrees for standard twist bits, or a flatter 135 degrees for tough metals like stainless steel.

What Happens if I Use Improperly Sharpened Drill Bits?

An improperly sharpened bit generates heat and friction instead of cutting, which can snap the bit, tear the material, or burn out the drill motor. Uneven lips are the usual cause. If one cutting edge is longer than the other, the bit drills oversized, wobbly holes and is far more likely to slip and injure you.

What Is the Best Drill Bit Sharpener?

The Drill Doctor DD500X is the easiest sharpener for getting consistent results. It has preset 118 and 135-degree angles and a diamond grinding wheel, so it holds the geometry for you and is hard to mess up. A bench grinder costs less and does more around the shop, but matching that accuracy freehand takes real practice.

Can You Sharpen Cobalt or Titanium Drill Bits?

Yes, you can sharpen cobalt and titanium-coated bits, but they are harder than plain steel, so reach for a silicon carbide or diamond wheel. Keep in mind that a titanium-coated bit is high-speed steel underneath, so sharpening grinds the gold coating off the tip and leaves a plain steel cutting edge, which still cuts fine.

What Is a Split-Point Drill Bit?

A split-point bit has two extra edges ground into the chisel point, turning the whole tip into one continuous cutting edge. That geometry lets the bit start on its own with less pressure and keeps it from walking across the surface, which is why it is common on 135-degree bits made for metal.

How Often Should You Sharpen a Drill Bit?

Sharpen a bit as soon as it stops cutting cleanly rather than on a fixed schedule. The tells are a bit that squeals, smokes, throws fine powder instead of chips, or needs you to lean on the drill. Catch it early and you get a quick touch-up instead of a long regrind.