how to sharpen drill bits

Know-How Notes: How to Sharpen Drill Bits The Easy Way

The easy way is often described by old-timers as the wrong way, but that isn’t always the case. Another way to put it is that there is the right tool for every job, and the same applies to sharpening drill bits. There is a right way to do it, and there is the best way to do it. Yes, you can absolutely sharpen drill bits using a bench grinder or small belt sander, but that method, while fairly simple, is not easy. You can absolutely destroy the cutting edge of your drill bit trying to figure out how to get the right angle. Why waste your precious time when there is a tool that can sharpen drill bits in less than 30 seconds each? With perfect results, every time, the Drill Doctor is your best bet.

As discussed in our recent article on drill bits, the most common bits use either a 118- or 135-degree angle. The Drill Doctor 500X is capable of handling both, with a simple adjustment. The machine can handle bits from 3/32”, on up 1/2”, up to 3/4” with an optional large bit chuck. It can also split points for self-centering. This tool is real time saver, especially when you have a bit that goes dull in the middle of project.

This is what happens when you have a dull drill bit. Note how the hole is off-center and the one side is galled. A sharp bit works better and faster than a dull one.

This is what happens when you have a dull drill bit. Note how the hole is off-center and the one side is galled. A sharp bit works better and faster than a dull one.

Sharp drill bits are safe drill bits. The act of drilling is quite literally a process in which material is ripped away from the main body. Dull bits cut slowly, require more pressure to cut, and increase heat put into the part. All of these things lead to off-center holes, ruined parts, and broken bits. Breaking a drill bit while drilling is very dangerous, often ending in a bloody mess on the bench because you impaled yourself. Sharp drill bit, just like a knife, cut the material quickly and efficiently, so that there is less trauma on the material, and less trauma on your human body.

Using a Drill Doctor is simple, we have put together a guide to using this tool to make sure your drill bits are sharp and safe. Begin by selecting your bits. Inspect the tip of each bit. If there are any chips or jagged edges, the bit needs to be sharpened. Carefully feel the edge; it should be sharp and not rounded. If one side of the bit is smaller than the other, the bit has been favoring one side; this is to be rectified by sharpening.

The edges are jagged and chipped, this bit will never make a clean hole.

The edges are jagged and chipped, this bit will never make a clean hole.

 

We painted the bit with some machinist dye to show the progress. You don't need to do this, but it is helpful.

We painted the bit with some machinist dye to show the progress. You don’t need to do this, but it is helpful.

Next, you need to decide what angle you want on the bit. Most hobby-grade bits use a 118-degree angle, and this is the standard angle setting on the Drill Doctor. You can change the angle of the bit, you just end up sharpening it a bit more to get a complete change. See our article on drill bits for more details on the differences between the two. A 118-degree bit has a sharper point, whereas 135-degree bits are more flat at the tip. With the Drill Doctor plugged in, but turned off, place the chuck into the alignment guide with the notch on the chuck in the 118-degree mark (straight up). If you are sharpening a 135-bit, adjust the chuck one notch to the right.

The bit we are sharpening is a 137-degree tip, so we set the bit holder in the 137-degree position, which is one slot clockwise of the 118 mark.

The bit we are sharpening is a 137-degree tip, so we set the bit holder in the 137-degree position, which is one slot clockwise of the 118 mark.

Open the chuck by rotating the grip. Slide the bit into the chuck until it reaches the clamp arms. Press the button to open the clamps with one hand, and slide the bit in place with the other. Release the clamps. The clamps will align the bit to the correct position. Tighten the chuck so that it grips the bit firmly. Make sure the bit has not dropped between the gripping blades inside the chuck.

The bit chuck has 6 teeth that grip the bit, open it up to accept the bit.

The bit chuck has 6 teeth that grip the bit, open it up to accept the bit.

 

Then close the chuck on the bit, just enough so the bit doesn't fall out.

Then close the chuck on the bit, just enough so the bit doesn’t fall out.

 

Load the chuck into the alignment port and set the notch in the desired angle position as discussed previously. The spring clips align the bit, and then the chuck is tightened to secure it.

Load the chuck into the alignment port and set the notch in the desired angle position as discussed previously. The spring clips align the bit, and then the chuck is tightened to secure it.

Next, select the drill angle on the Drill Doctor’s sharpening port. Loosen the knob and lift the port to match the desired angle, 118 or 135.

There are two settings on the Drill Doctor, 118 and 135. We selected 135.

There are two settings on the Drill Doctor, 118 and 135. We selected 135.

Turn the machine on and insert the chuck into the port. Slowly push the chuck into the machine until the chuck is seated in the port. You may hear the bit contact the spinning sharpening head.

With the chuck in the sharpening fixture, press the rocker up to the follower pin and slowly spin the chuck, counting each full revolution, until the grinding is complete.

With the chuck in the sharpening fixture, press the rocker up to the follower pin and slowly spin the chuck, counting each full revolution, until the grinding is complete.

Push the guide port up until it touches the pin at the top. You are ready to sharpen. Slowly spin the chuck clockwise, counting each half rotation. Every even number is one turn. Most bits take 20-40 spins to complete the sharpening process. Work the bit until it does not grind. You can check your progress occasionally as you go.

The grinding stopped, but the bit is not sharp yet, you can see the chipped edges and dye still.

The grinding stopped, but the bit is not sharp yet, you can see the chipped edges and dye still.

 

The bit seemed to have slipped back a little, so we realigned it and started again.

The bit seemed to have slipped back a little, so we realigned it and started again.

A properly sharpened bit will have clean chisel (cutting edge), a heel that is lower than the point (called positive relief), and the chisel angle should be at 1-1:30 when looking at the bit as shown. If the angle is at 2 o’clock, try again, only move the notch 1 to 2 places to the right. If the chisel angle is at 12:45, move one to the left. You can fine tune the angle to match your bit, which is one of the great things about the Drill Doctor.

A completed sharpening, this bit looks good.

A completed sharpening, this bit looks good.

If you not splitting the point, you are done. If you are splitting, the point, then keep the bit in the chuck and move to the next step. Splitting the tip on a bit is super easy with the Drill Doctor. After sharpening, simply insert the bit into the splitting port (on the side of the machine), and slowly press it into the running sharpening stone. Take the chuck out, rotate one half turn, and repeat. Two steps, all done. A split tip with help keep the bit centered in harder materials.

The port on the side is for tip splitting, which helps keep the bit centered.

The port on the side is for tip splitting, which helps keep the bit centered.

 

A few seconds on each side and you are good.

A few seconds on each side and you are good.

 

This bit is fully sharpened with a new split tip. Ready to make some holes!

This bit is fully sharpened with a new split tip. Ready to make some holes!

Sharpening drill bits by hand is an art form, one which while certainly useful, is hard to learn and takes a lot of time. The Drill Doctor is simple to use and well worth the money to get the job done. This author regularly puts his 13 year old son to work in the shop with a bucket of old drill bits and the Drill Doctor. It is that easy.

Check out all the tools & equipment available on NAPA Online or trust one of our 16,000 NAPA AutoCare locations for routine maintenance and repairs. For more information on how to sharpen drill bits, chat with a knowledgeable expert at your local NAPA AUTO PARTS store.

about author

Jefferson Bryant

A life-long gearhead, Jefferson Bryant spends more time in the shop than anywhere else. His career began in the car audio industry as a shop manager, eventually working his way into a position at Rockford Fosgate as a product designer. In 2003, he began writing tech articles for magazines, and has been working as an automotive journalist ever since. His work has been featured in Car Craft, Hot Rod, Rod & Custom, Truckin’, Mopar Muscle, and many more. Jefferson has also written 4 books and produced countless videos. Jefferson operates Red Dirt Rodz, his personal garage studio, where all of his magazine articles and tech videos are produced.

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