Have you ever tried to use a dull knife to cut into a hard vegetable or a loaf of bread? It’s a challenge, not to mention dangerous because the knife could slip, leaving you with a bleeding hand or finger.
Just like your kitchen knives, the drill bits you use to make holes in a variety of materials also lose their sharpness over time. A dull drill bit isn’t only more difficult to use, it’s also more dangerous.
The good news is that you don’t have to replace dull drill bits. Learning how to sharpen drill bits means you can restore them to their former glory.
The Anatomy of a Drill Bit
Before you sit down and learn how to sharpen drill bits, it’s a smart idea to have an understanding of what makes up a drill bit and how bits work.
Drill bits are able to cut through materials thanks to a point angle. The flatness of the angle determines the type of material the bit can cut.
For example, if you’re cutting a relatively soft material, such as wood or drywall, you’d use a drill bit with a point angle of 118 degrees, according to DoItYourself.
But if you’re trying to drill through something harder, such as concrete, you want to use a drill bit with an angle of 135 degrees.
The tip of every drill is shaped like a chisel point. A sharp chisel point easily breaks through whatever material you’re boring into.
Next, the cutting lips, which spiral up the length of the bit, help to cut and push the material away. Any excess material gets transferred to the flutes, the depressions between the cutting lips, and out of the hole.
Your drill bits are most likely going to wear down along the cutting lips, but it’s also possible for a bit to become dull at the chisel point.
Why Sharpen Drill Bits?
Just like a new car, a drill bit starts to wear out the minute you start using it. Unlike a new car, it’s relatively easy to restore a drill bit to its original sharpness.
If you’re wondering why sharpen drill bits rather than just let them be or replace them, here are a few reasons.
- Reduces the risk for injury. There’s a saying in professional kitchens: Dull knives cut fingers. The same is true of drill bits — the duller they are, the more likely they are to cause injury.
- Reduces the chance that the bits will break. A broken drill bit can easily turn into a projectile if it snaps mid-drilling. It’s also a waste, as you’re stuck having to go out and buy new bits.
- Protects your drill. Your fingers, eyes and face aren’t the only things that can be damaged by a dull drill bit. The duller the drill bit is, the harder your drill has to work, which can really put a strain on the motor.
- It’s cost-effective. It’s often much cheaper to sharpen the bits you already own than to go out and buy new ones.
- It ensures a clean cut. Sharp drill bits are able to neatly cut through a variety of materials. When bits get dull, they tend to catch on the things they are drilling into, which can make your finished project look a lot less neat.
What’s the Best Way to Sharpen Drill Bits?
Is there a best way to learn how to sharpen drill bits? Not necessarily, but some tools do make the process of sharpening bits a bit easier.
One of those tools is a bench grinder. A bench grinder features a motor and a spinning wheel on either end.
The wheels consist of a gritty, abrasive material that grinds down the edges of your drill bits, restoring their sharpness.
Here’s how to sharpen drill bits using a bench grinder.
What you need:
- Dull drill bits
- Safety goggles
- Bench grinder
- Bowl of water
- A piece of scrap wood
What to do:
- Put on your safety goggles. Small pieces of metal might go flying as you work. Protecting your eyes is a must.
- Turn the bench grinder on. Bench grinders have two wheels, one with a rough, coarse texture, one with a finer texture. Use the coarse wheel for very dull bits and the finer wheel for bits that aren’t so worn down.
- Place the cutting lip of the drill bit against the wheel of the grinder at a 60-degree angle. Getting the angle right is a must, otherwise you risk messing up the drill bit.
- Hold the bit against the wheel for just a few seconds. Any longer and it will get too hot or the blade will wear away too much.
- Dip the bit in the bowl of water. Doing so will cool it off.
- Inspect the bit. Is it sharp enough? If not, grind for a few more seconds or switch from using the coarse wheel to the finer wheel.
- Rotate the bit 180 degrees. Turn the bit around and start to sharpen the other side.
- Use the same method, holding the bit at a 60-degree angle to the wheel. Grind away for a few seconds, then dip the bit in the water to cool it off.
- Test the sharpness of the bit. Gently push the bit into the piece of wood. If it’s sharp enough, it should start to make a hole.
If the bit’s not sharp, repeat the process again.
How to Sharpen a Drill Bit Without a Bench Grinder
While a bench grinder can make easy work of sharpening a drill bit, what if you don’t have one handy? You can still sharpen your drill bits, using a metal file.
What you need:
- Dull drill bits
- Safety goggles
- Auger file
- Vise or clamp
- Lubricating oil
- Cloth or rag
What to do:
- Put on your safety goggles. Secure the drill bit to a surface by placing it in a vise or by clamping it down. You can hold the drill bit in your hand while you file, but it will be a bit awkward.
- Rest the file on one of the drill bit’s blades. Hold the file at a 60-degree angle. Drag the file along the edge of the blade about seven times.
- Repeat on the other side of the drill bit, on the opposite blade.
- Clean up the drill bit. Run the file along the underside of each blade to remove any burrs.
- Oil the drill bit. Place a drop of oil on each side of the drill bit and rub it in with a soft cloth.
How to Maintain Your Drill Bits
Although you can’t keep drill bits from becoming dull, how you use the drill and how you care for the bits can help to extend the time between sharpening. Here are a few ways to keep your drill bits sharper for longer.
- Clean the bits as you drill. When making a hole, pull the drill out from time to time and clear away any debris and dust that’s collected in the flutes on the bits. If left in place, the dust and debris can get packed in, causing the bit to heat up and become duller faster.
- Cool the bit often. Keep the bit cool while you drill by dipping it in a bowl of water or by spraying it with water.
- Oil the bits between uses. A rusty drill bit is pretty much an unusable drill bit. To keep your drill bits from becoming rusty, apply a coating of oil after each use.
- Store drill bits in the right place. Where you store drill bits can affect their lifespan and quality. Avoid humid areas if at all possible.
Final Thoughts on How to Sharpen Drill Bits
There’s the old saying that it’s important to have the right tools for the right job.
Perhaps even more important than that is having the right, well-maintained tools for the job. Trying to work with dull drill bits is only going to lead to frustration, if not injury.
Thankfully, learning how to sharpen drill bits isn’t too challenging. There’s a considerable amount of room for error, and if you mess up the first time, you can always go back to the grinding wheel and correct your mistakes.
Whether you end up investing in a grinding wheel or use a file to sharpen drill bits, the important thing is that you keep up with sharpening on a regular basis. If you notice any difficulty when drilling, the best thing to do is try to sharpen the drill bit.
Now that you know how to sharpen drill bits, it’s up to you to take good care of your tools so that they’ll last you for years to come.