Introduction: Sharpen Your Drill Bits

Picture of Sharpen Your Drill Bits

Sharp drill bits are fun to use. They work so well. Dull bits are dangerous. They can break. One broke for me once and went through my thumbnail and out the other side of my thumb.

Step 1: A Dull Bit and a Sharp Bit

Picture of A Dull Bit and a Sharp Bit

The bit on the left is a little dull. Notice the glint of light on the cutting edge between the two flutes. Compare that with the crisp edge on the freshly sharpened bit on the right.

Step 2: My Favorite Sharpening Tool

Picture of My Favorite Sharpening Tool

People who know what they are doing can sharpen bits by hand. In theory, hold the bit with the shank angled off to the left at about 59 degrees. As the bit contacts the grinding wheel, simultaneously move the shank farther left and downward while twisting it clockwise. I have tried, but I have never been able to make it work for me.

I bought this bit sharpening tool almost 30 years ago for less than $20. The same tool is still available at Amazon and other places, and it is still less than $20.

A Drill Doctor is a very nice tool, but it costs four or five times the cost of this tool. I do not sharpen bits often enough to justify the cost of a Drill Doctor.

Step 3: Set to 59 Degrees

Picture of Set to 59 Degrees

This sharpening guide can accept drill bits with several different profiles. My bits have a 59 degree profile on the cutting edge. Set the tool to 59 degrees and tighten the thumbnut.

Step 4: Catch the Edge

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The tool has a small tip and the edges of the bit's flutes rest against it. You may have to raise or lower the tip so it fits against the flute edges properly.

Step 5: How Much Overhang

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As a starting point make the overhang (space between the yellow lines) equal to the radius of the bit (space between the green lines). See the next step for why it matters.

Step 6: Width and Angle of the Cutting Edge

Picture of Width and Angle of the Cutting Edge

Notice the angle of the red line. If there is too much overhang in the previous step, the red line will approximate the cutting edge at the tip of the bit. It is too wide and the bit profile will be too flat. The bit will skate on a metal surface and the hole will be hard to start. You can reduce the bit's overhang quite a bit, but be careful. If you reduce it too much, the tip you adjusted in step 4 may come into contact with the grinding wheel and you will damage your sharpening guide.

Step 7: Ideal Cutting Edge Angle

Picture of Ideal Cutting Edge Angle

The ideal is to have the shortest cutting edge possible. This would be a cutting edge that runs between the low points in the valleys of the fluting. See the yellow line. This bit is close to ideal and will cut steel very well.

Step 8: Clamp the Bit in the Tool

Picture of Clamp the Bit in the Tool

When you have the overhang set, turn down the screw that clamps the bit in the tool's trough.

Step 9: Set the Tool for Bit Length

Picture of Set the Tool for Bit Length

Set the sharpening guide for the length of the bit you want to sharpen. Keep the end of the bit in the moveable trough, not hanging in the air. Loosen the metal colored nut. Adjust the black nut. Tighten the metal colored nut.

Step 10: Align for Height

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The end of the bit should be squarely aligned with the grinding wheel. I use a radial arm saw for my grinding. The tip of the bit should be even with the center of the motor shaft.

Step 11: Clamp the Tool to the Table

Picture of Clamp the Tool to the Table

You want the bit to kiss the grinding wheel while sharpening it. If the bit is too close to the grinding wheel; sharpening will be difficult, the bit will become too hot, and you will remove a lot more material than necessary.

Keep the base of the sharpening guide square to the surface of the grinding stone (green lines), but turn the upper portion of the guide so the tip of the drill bit is just a little to the left of the center (angle between long green line and the yellow line). Slide the guide forward so the bit lightly touches the grinding wheel's surface. Clamp the guide to the table.

Step 12: Get Ready to Grind the Bit

Picture of Get Ready to Grind the Bit

Swing the tip of the bit to the right. Start the motor.

Step 13: Grind

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Swing the rear of the sharpening guide to the right (red arrow) so the tip of the bit moves into the wheel. The yellow shower of sparks is added in a photo editing program, but the actual grinding happens when the bit is in about this position.

Step 14: Rotate the Bit One-half Turn

Picture of Rotate the Bit One-half Turn

Continue swinging the guide until the tip of the bit is beyond the cutting wheel. You need to rotate the bit one-half turn and repeat the process in order to sharpen the other half of the bit.

It is safer to turn the motor off and wait for the wheel to stop. Loosen the hold down on the bit and turn the bit one half turn. Make sure the flute rests on the guide's tip. Repeat the process from the last two steps.

Shut the motor off. Remove the bit. Check width of the center cutting edge on the bit. Adjust the overhang and repeat the grinding process if it is not satisfactory.

Step 15: The Finished Bit

Picture of The Finished Bit

This is how your bit should appear. Notice there are no longer any worn, rounded cutting edges casting glints of light. Everything is sharp and crisp. The length and angle of the cutting edge at the tip of the drill bit are good, too.

Step 16: Small Sizes

Picture of Small Sizes

A sharpening guide like this one works well for bits 1/8 inch and above. It does not work with smaller bits than 1/8 inch.

Make a special wooden block to serve as a guide for a handstone when sharpening small bits. The angle of the lines in red is 77 degrees. Make the block about 4 inches long.

Step 17: Compound Angles

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This is the edge of the block. The angle between the red lines is 59 degrees.

Step 18: A Guide Line

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Notice the "V" in the top surface of the block. It runs the length of the block and makes a place for the small bits to be cradled. The angle between the red lines is also 59 degrees. This serves as a guide line to align with the leading edge of each half of the bit. A visual alignment is satisfactory.

Step 19: Placing the Bit Against the Block

Picture of Placing the Bit Against the Block

Place a bit into the "V" groove on the back face of the block. Place the block into a vise so the end of the bit rests on top of and against the jaws and so that it just barely extends above the angled surface of the block. Turn the bit so the leading edge of the first half follows the guide line. Use a "C" clamp to hold the bit in place. Put some oil on a small handstone, like those used for sharpening fishhooks. Stroke along the angled surface of the block so the bit is being sharpened at the same time. When the stone is no longer cutting on the bit, turn it half of a turn and sharpen the other side. Inspect the bit with a magnifying glass, if necessary.


theoldguy (author)2017-12-19

Freehand sharpening. Hold the shortest thickness at the point vertical. angle the drill up and down WITHOUT turning it.

The skill is in the angle of the drill to the vertical. If you go all the way to horizontal you have no clearance. And remember the two main things. 1 keep the shortest part of the web at the tip vertical and 2. Don't turn the drill at all when grinding just change the vertical angle.

WilliamD237 (author)2017-11-25

2 questions :

1. How do I find the correct angle of my drill bits?

2. Whereas you use a radial saw, I have access to a bench grinder with a small wheel, how do I get my hight alignment?

Thanks in advance.

Phil B (author)WilliamD2372017-11-26

Most probably the angle on your bits is 59 degrees. That is pretty standard unless you have a very specialized bit.

Although it is not generally recommended practice, you can sharpen bits on the side of the grinding wheel rather than on the circumference of the wheel. Can you temporarily mount your bench grinder on a riser of some kind?

WilliamD237 (author)Phil B2017-11-28

thank you much. worked out perfectly.

Phil B (author)WilliamD2372017-11-29

Thank you for the update.

Mahku (author)2017-11-23

I was struggling with the General drill bit sharpening guide and then found your article. I think it will help. Thanks.

Phil B (author)Mahku2017-11-23

Welcome to Instructsbles. I learned some minor things from my own use, particularly what is in step 11. Check the results you are getting as you go and make minor adjustments. Unfortunately, it is easy to grind away part of the tip against which the flute rests. I began with the directions included with the device and made common sense tweaks. From my side, the purpose of this Instructable was to record those so I did not need to reinvent the wheel after a long period of no use. Since posting this, I finally learned to sharpen drills by hand. It is not nearly as difficult as I thought. A couple of videos at YouTube were very helpful.

manistylinson (author)2017-11-22

Where can i buy that sharpening tool ? I searched on Amazon but i didn't find it ,can you send me the link? Please?

Phil B (author)manistylinson2017-11-23

Amazon does have it as a General 825 drill sharpener. Search for that. It is about $25 plus shipping, etc.

paolo1968 (author)2016-12-31

Inspired by this amazing guide I made this configurable block

MikeC286 (author)2016-04-21

This is a great guide and I managed to get a reasonable edge on my first bit! However I am puzzled by the setup with the drill slightly to the left and then sharpen it from the other side... Ie from right towards the left. As the bit kisses the wheel when setup to the left, how can it be turned back to the right to start sharpening when it will pass through the wheel? If you need to move it the why set it to the left in the firdt place? Also after the first pass how is it returned to the right? Or is grinding done in both directions?
Thanks again

Phil B (author)MikeC2862016-04-22

You can sharpen by swinging the fixture both ways. What I found was it is tricky to know how close to set the fixture (and the front end of the bit) to the wheel. Swinging the axis on the fixture a little to the left and then moving the fixture up to the wheel so the bit touches the wheel grinds just the right amount off of the end of the bit without grinding either too little or too much. It is just a little thing I discovered for getting the right starting point. I think if you try it y will see why I do it that way.

cpennell1 (author)Phil B2016-07-11

great tutorial! I have the same Craftsman sharpening tool, inherited from my grandfather and I am excited to salvage some wrecked and worn bits. thanks!

Phil B (author)cpennell12016-07-11

Thank yu for looking. Feel free to make adjustments so you get the best results.

ptuan (author)2016-03-31

Hey thanks for this awesome guide. I was very perplexed at first on how to operate my drill bit machine, but now I know how. Anyway, I think Drill Doctor sharpener is very good at this job, as I search around for reviews and all recommend this brand, especially this

Phil B (author)ptuan2016-03-31

I hope it is helpful to you. A friend has a Drill Doctor machine. I used one belonging to my son-in-law. Afterward, I talked with my friend. We agreed a Drill Doctor sometimes does a good job, but there are times when it does not do well at all. I was surprised. I had always thought they would be a sure-fire method. In recent months I have finally learned how to do a fair job of sharpening drills by hand. My results probably are not perfect, but the drills certainly work far better after I am finished with them than they did before.

borentpa (author)2015-07-26

I can't believe it...I bought one of these bit holders at a tag sale several years ago. ..brand new in box for $2.00..but no instructions. ..thank you for the great HANDS ON INSTRUCTIONS. .

Phil B (author)borentpa2015-07-27

Thank you for your note. Congratulations on a really good deal. I bought mine new and instructions were included. But, there wee still some fine points to learn by experience. I wanted to share those so the instructions and the sharpening jig are more useful.

Be sure to make a wood block with sloped cuts for sharpening small bits 1/8 inch and smaller. Just a few weeks ago I made one of those blocks for a friend who owns a Drill Doctor. He said no matter what he did he could not make his Drill Doctor hold the smaller bits for sharpening. I sharpened a 1/8 inch bit for him in a couple of minutes with the wooden block and a sharpening stone. He drilled some oak and was very pleased to have a sharp bit again.

GregoryD (author)2014-09-11

basic question: What is the "web" of a drill bit?

Phil B (author)GregoryD2014-09-11

It is the short peaked edge of the bit between the two fluted sides of the twist. You can search for bit web at YouTube for a video on now to shorten it.

padbravo (author)2014-01-28

Thanks for this instructable!
I will try to follow your instructions to do it...
I found a place to get this adapter, and with your guidance, maybe I can master this dark art

bakichmg (author)2013-05-13

I recently purchased this sharpener. I am totally confused by the instructions that came with it. I am glad I found your instructable. But I still cannot figure out the proper position of the bit. Which way is the bit supposed to be twisted in the holder?? I have tried it may different ways and the grinding angle comes out wrong. Can you please help me?? Do you possibly have a close up of the bit installed with the proper orientation??

Phil B (author)bakichmg2013-05-13

Do the photos and the descriptions in steps 4 and 5 make sense to you? If not, what puzzles you about them?

bob Cosenza (author)2013-04-20

Machinist by trade, machine grinding is ok, but even with this drills are touched up by hand, back clearance and the web is thinned out ( aircraft colbolt drills) by hand.

inad (author)2009-05-08

This is a great series. Wonder if you could do a parallel instructable showing free hand held technique for sharpening drill bits. some oblique photos would be a great help.

Phil B (author)inad2009-05-09

Thank you. I am glad you like it. I hope it helps you when you sharpen drill bits. If I had mastered sharpening bits by hand, I would gladly do an Instructable on the process. I did find a couple of pages that briefly describe how to do it, and alluded to the basics early in this Instructable. Perhaps one of the previous commentators who has learned how to do it would consider producing such an Instructable. I do not believe myself to be qualified to do it.

jack8559 (author)Phil B2010-11-10

As a machinist, I have sharpened thousands of bits - all by hand. If they are really small (under 1/8") I usually just get a new one since we never had a sharpener that I had any degree of faith in. A note for everyone that attempts to hand sharpen a bit... always look to be sure that from the cutting edge that there is relief behind it. I have seen so many people that claim to be able to sharpen a bit and they come back with the trailing edge of the bit higher than the cutting edge and they wonder why it won't cut.
If a bit is going to be drilling hard material, you will want the end to be more flat so it won't dig in and dull fast, and you will ALWAYS want to center punch your mark to prevent a drill from 'walking'. The 59° angle used on most sharpeners is a standard angle for mild steel - for softer materials make the point more like a pencil but be careful of how much more pointed you make it, it could try to screw itself into the wood, plastic or whatever you're drilling. I guess my point is to go in small steps until you know what works for you!
Try starting with a large bit if you aren't familiar with the procedure and remember that if the steel gets hot enough to turn black at the cutting edge, you have just removed the carbon from the edge and it will dull VERY soon. You must grind the metal slowly and dip in water or some other coolant frequently so as to prevent that. Get a new bit to look at after you have tried your hand on a big one and see what the difference is, there should be very little. When thinning the web, remember that the thinner the web, yes, the easier it will penetrate the work, but also the easier it can grab and split the drill down the center making the drill bit trash immediately. If the sides (lands) are worn on the drill bit, it WILL grab and break off many times when you need it most - inspect drills before using them to keep from ruining your project... After grinding, hold the bit up with a bright background behind it and with the cutting edges going left and right from your body - you need to make sure that both the tips are the same height and that the point is in the center before you attempt to thin the web if it is needed. If there is a pilot hole with a greater diameter than the thickness of the web, no thinning will be required.
Whne grinding by hand, always hold the cutting lip level against the wheel at the center height of the wheel and rotate the drill upwards to make the relief. Grind slowly and don't try it with a wheel that is out of round, you will get hurt badly. Dress the wheel to be true before starting any grinding process. Always use safety glasses or goggles when grinding and if there are any questions, stop what you are doing and research it- SAFETY FIRST!!

Bowtie41 (author)jack85592013-01-04

I know it's an old post,but Bravo!

nedward (author)jack85592011-11-04

do you use a slow grinder 1800 revs i am a qualified electrician from sout africa rsa southafrica i use a norton white stone on 2400 rev grinder small bench grinder i find the grey stones hard on the drill only use white wheel i come from a farm where we sometimes use an angle grinder for a quik sharp your article is exellent with safety and all is the relief part the thickside from the cutting edge downwards 118 degrees on the slope on both sides must be even it is an art to grind freehand but i cant sit in the field with jigs the work must go on blunt drills scream i also use lubricant when drilling electrical cuttinpaste nice talking to you nedward

jack8559 (author)nedward2011-11-04

At work, I used a regular bench grinder, which means that you need to lightly touch the bit to the spinning stone, rotate the bit, cool it in coolant preferably, but just plain water will do fine, repeat until you have finally got it really close enough to suit you, then gently and lightly grind the finishing touches all the way from the cutting lip to the trailing side to get the relief right and cool it again. It takes a while to get it right. A great thing to do is get a new bit and never sharpen it, just use it to look at while grinding the old bit so that you know what you're looking for in the hand sharpened bit - use it as a comparison for the point.
The 59 degerees is the angle on one side of the bit to the centerline of the bit, so the 118 degrees that you mention is the same as what I'm doing. The finer the grit you use means that you will have to dip it in water or coolant more frequent but it will give you a better grind as well. I have used a 60 grit wheel and gotten good results, it's just a matter of taking your time and knowing what to do. Practice makes perfect, and then when you think that you've got it, then practice a lot more..... you'll see that there are ways to do the job and make it a lot faster and still not burn the bit! If you never have made the metal black or blue at some point during sharpening the first hundred bits, you have not really tried like you should. Know when it will turn blue and stop short of that. Small bits will turn blue a lot faster than larger ones due to the mass that will have to be heated from friction to cause it to turn color and burn the carbon out...

Phil B (author)nedward2011-11-04

The motor on my grinder runs at 3000 rpm. I use what I have available. I do not have a white stone. Thank you for looking and for commenting.

MTJimL (author)jack85592011-06-17

I thought I was good using a drill guide and sharpening by hand. Being able to accurately eyeball the slope, clearance and centricity without a guide seems truly remarkable.

jack8559 (author)MTJimL2011-06-17

This is not something that you can pick up in a few days, maybe not in a year. I have sharpened bits for over 25 years (daily) to do as well as I do. The first thing that someone needs to do when attempting to sharpen by hand is to really study drill point geometry closely. Understand all the parts of the drill and what their specific function is and why it is needed to be the way that it is. Once you understand all this, you must try a few thousand bits before you get it close enough to perform well for your application consistently.

One point to remember is that the angle of the point must be reasonably close to what is recommended for the application that you are going to use it for. the more pointed it is, the more it will tend to pull itself into the material being drilled, so that material must be soft enough not to split the drill down the web. The harder materials will be better served drilling with a much less point on the drill - almost a square end. The relief behind the cuting edge has a bearing also - hard materials need to have a relatively low relief (.001 to .003") and softer materials like wood should have a more pronounced relief(.010 to .020"). If a material is not drilling fast enough, it is probably due to the web being too thick and must be thinned OR the relief is way too shallow. Be careful to closely inspect the lands for drilling materials like bronze, this material tends to wear out the lands and the drill will grab and split the drill down the web and break off in the hole - not a pleasant task to remove. It takes some homework to fully understand drill bits even though they are as common as they are.

tomas.savage (author)jack85592011-06-09

good advice. i'm a jeweler and i sharpen my tiny drill (1.5mm or smaller) bits by hand all the time. i use an ultra-thin cutting disc and hold the drill in a pin vice. it was a matter of trail and error until i learned how to hold the bits and tools at the proper cutting angles. the cutting disc can even sharpen/deburr worn lands by running it through while rotating the pin vice.

[note: with this method, it is even possible to restore some life to other rotary tool bits, though i would use them for roughing work]

Twicewidowed (author)jack85592011-06-09

As an old time machinist (now 84 yo) I agree. Hand sharpening drills is an art learned over years of experience. Production drills should always be machine-sharpened however. Two equal sized spirals of blue hot steel emerging from a bath of cutting fluid is the mark of a well sharpened drill but having the ability to touch up a slightly dulled drill by hand is a real time saver and an indication of craftsmanship.

baudeagle (author)jack85592011-06-06

Great response, your comments above are in essence the same as what a mold maker taught me a long time ago.

One tip on drilling large hole, if using a pilot drill, use a small diameter drill compared to the diameter of the finished hole. The the pilot drill should not be smaller than the thickness of the larger drill's web.

Thanks for your comments.

Phil B (author)jack85592010-11-11

Thank you for a very helpful comment. Regular practice has to be a key component in the proper sharpening of bits by hand. Even if I was careful to keep the heel lower than the cutting edge, I had trouble getting the slope angle equal on both sides and with keeping the web centered between the opposing sides of the bit. I stand in awe of anyone who can sharpen bits by hand and do it right.

jack8559 (author)Phil B2011-06-17

I don't have access to a camera or recorder, but there is a book that may help if you can find a machinist or engineer that will let you look through their copy. It's called MACHINERY'S HANDBOOK. The book is expensive, at least by my standards - around a hunderd bucks US money. There is a wealth of information in there on a lot of things mechanical. You may be able to find an old used one on ebay or someplace for 30 or 40 dollars - well worth the money!

anode505 (author)2011-06-09

I disagree with the ability to sharpen by hand. Yes it will be sharp, but right? Doubtful. Unless both sides are even, it will not cut the correct sized hole.
People that claim they can do it are just lucky once in a while. I say test a hole with a pin gauge; you'll find its cutting large.

ArtisanEclectic (author)anode5052012-06-03

I have sharpened many bits by hand on a bench grinder. It only takes a little practice and attention. I've used them to drill wood, plastic, aluminum, and stainless. Although I usually buy new Carbide bits for stainless. It's not rocket science. And I don't believe in luck.

Bowtie41 (author)ArtisanEclectic2013-01-04

I would like to add unless the carbide drill is about 1/4" or larger,to try not do it by hand,as carbide is very brittle,and any side-force just breaks them.Normally,any carbide drill should be in a press or mill with a rigid spindle.

Bowtie41 (author)anode5052013-01-04

As a machinist for 25 years I have to disagree.One of the 1st skills taught was how to sharpen by hand with a simple drill point gage.I remember a job over 20 years ago that we had to use a 1/32"(.031) drill to peck drill about 3/4"(.750) deep in stainless.They would not fit our drill sharpeners,and since I was one of the better sharpeners there,I got the task of setting at a grinder with a large magnifying glass,and a sharp edge orange wheel,and doing it "old school".As I sharpened several hundred bits for the screw machines,I had approx. 1-100 I would get an oversize hole or the bit would wander off-center and come out the side of the part,and I would have to resharpen again.I am not saying that to brag,just that there are literally thousands,maybe tens of thousands of us out here who do them by hand.I can't even remember how many I've done over the years,including split points,and making special diameter stepdrills,but it amounts several,several thousand.It is not a hard skill to master,just decent eye-hand coordination,but does take patience,and attention to detail at first.

stoobers (author)anode5052011-06-09

The hole down the center of a gun barrel is cut with a drill bit with a SINGLE flute - not even a double flute! And the hole is straight and true for several FEET.

You don't need two sides to the bit to make the bit cut. If you have a bit with two flutes, the bit will cut twice as fast as a singe flute bit.

Upon close examination, a two-flute bit will cut a triangular shaped hole! (trochoidial shaped). If you want the hole round, drill it 1/64" under and ream it out. If you need to thread the hole, you can skip the ream.

HoldOnTight (author)2012-07-09

I used to have one of these tools and I could never get a sharp bit with it. I'm happy that this tool works for you but it seems as though I couldn't get mine "dialed in." Replacing a bit every time one became dull was getting expensive. This tool probably doesn't handle the specialty bits with cuts to reduce friction, but a Drill Doctor does that. The diamond wheel on a Drill Dr. removes material very quicly, before the metal can heat up and destroy the hardness.

shazni (author)2012-05-08

how do i shapen a spiral scroll bit which is supposed to cut sideways too?
it's 1/8"...i use it for my rotary tool and i only can get new once from abroad

Phil B (author)shazni2012-05-08

I would get a fine, hard stone like a hard Arkansas stone and dress the bits by hand. It is not perfect, but it might help you.

shazni (author)2012-05-08

how do i shapen a spiral scroll bit which is supposed to cut sideways too?
it's 1/8"...i use it for my rotary tool and i only can get new once from abroad

flywelder (author)2012-03-01

Phil or any body,
I have inherited three drill bits made by the Union Twist Drill Co. a No. 8,
No. 6; and No. 9 They need sharpened, and I have yet to find any one who can sharpen these or tell me how to . the interesting thing about these bits is they each have three cutting edges. yes three. there is a pencil point surrounded by three flutes. Help.

Phil B (author)flywelder2012-03-01

Wow! I have heard of numbered sizes. When you want to drill for tapping threads the recommended bit is usually a numbered size. But, I have never heard of a bit with three flutes. I would ask questions at a local machine shop to see if they can help.

ronbuffington (author)2011-07-26

I thought these were called drills, not bits. Drills may be used with drill motors, but bits are used with a brace, i.e. a brace and bit.

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