Are you looking to learn how to sharpen drill bits?
Awesome. You are in the right place.
If you use drill bits quite a bit, you would have often noticed that at some point they no longer work as well as they used to.
This basically leaves you with two options:
- Buy a new drill bit; or
- Sharpen your existing drill bit.
No matter whether you are a weekend warrior or an avid DIYer you could definitely save yourself some money by learning the simple steps required to sharpen a drill bit.
In this ToolsGaloreHq.com guide, I will show you:
- 3 key parameters required for a successful re-sharpening;
- Steps on how to perform a drill bit sharpening;
- The equipment that you will need to undertake this successfully; and
- The fuss about the 118° and if it really matters.
Before we get into it, be sure to check out the table of contents below.
What You Need To Know About How To Sharpen Drill Bits
For anyone who has ever drilled a hole in a wall, piece of wood or steel, you know very well the amount of strain that your drill bit will endure.
Now as you use your drill bit more and more it will slowly loses it’s leading edge and it becomes what is referred to as “dull”.
Before I explain the necessary steps you must take to ensure that you can sharpen you drill bit successfully, there are a couple of fundamentals you must understand about your standard drill bit.
The 118° angle – how it affects drill bit sharpening
Before I get into the 118° angle. Let’s take a step back and think about how a drill bit actually drills through material.
The leading edge as shown in the image below is responsible for the strength of the drill bit.
The larger this leading edge, also sometimes referred to as the web, the more torque the drill bit can take.
Also drill bits are often made from High Speed Steel (HSS). Which is more durable and harder than your typical cold roll steel.
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Most standard drill bits operate off an angle of 118°. What this means is that when the drill is new out of the box, you will have and angle across the two heels of 118° as shown in the image below.
However, as you already know when drilling into steel or metal the high speed steel will still go dull. But you might be thinking what is a dull drill bit anyways?
Let’s take a look at an extreme case, image you tried to drill into a piece of stock material with a flat edge, you would not get very far no matter how much speed you rotated it.
The reason for this is simple the surface area for the torque is far to large and dispersed to create any sort of penetration through the material.
Infact, I can tell you what would happen. The flat edge material would just heat up quite a bit and not get very far into the metal or wood.
Many years of research have provided that the 118° angle is optimal. Therefore when your drill bit (which is typically high speed steel) loses it’s ability to drill effectively and thus becomes dull, it is because technically the angle has become reduced.
Now that you know this to get your drill bit back into tip top shape all you really need to do is restore the drill bits tip back to the original 118°.
Drill bit sharpening kits (what is all the fuss)
If you go to any hardware store or convenience store that sells drill bits, you will usually also find a section that sells some form of drill sharpening kit.
It’s a mechanical looking contraption that is designed to hold your drill bit at a specific angle to ensure that you can have nice and smoothly sharpened bits.
In my opinion, these drill bit kits are not really required, especially if you have a grinding wheel slot that can maintain the an angle with some flexibility to allow you to rotate the drill bit a little for smooth sharpen.
3 key things you must get right to sharpen you drill bit correctly
No matter which method you use either a drill kit or using a grinding wheel without any support there are primarily 3 things you must get right to ensure a solid drill finish. See the image below and lets discuss these.
The very first is symmetry.
You must ensure that as you are sharpening your drill which shall be explained below, you maintain symmetry on both sides.
The reason for this is because the drill will be rotating around the chisel point (tip). If the sides are not symmetrical this puts further mechanical stress on your drill bit.
Plus - Reducing it’s overall life and making it harder to maintain stability.
The second critical item is your cutting edges should be identical. From the image above if you look carefully they are not 100%, but they are reasonable the same. Which is generally adequate.
Read More:>>> Learn more about edges and split point drill bits
One thing I want to point out is that sharpening a drill bit is definitely not an exact science.
If you can get approximate values you generally will be alright.
Lastly, you will need a tilt angle. This is very important. The tilt angle basically helps funnel the material and debris through your flutes. Without this angle it would be like you are trying to drill with a flat face. Your drill bit would just overheat unnecessarily.
Whenever you are working with high speed steel or rotating mechanical parts such as drill bits, you should always equip yourself with personal protective equipment.
I would go as far as to say that you should never deal with such equipment without the use of protective workman gloves and eye protection for small metal splinters.
It is generally recommended to also use ear protection as this will reduce the likelihood of any damage that can be caused from the high pitched noise as you sharpen.
Equipment You’ll Need To Know How To Sharpen Drill Bits
To perform this task you do not require to much in terms of equipment. All you will need are namely:
- Angled jig (buy it or get it custom made)
- Grinding wheel
- Blunt drill bit
- Drilling fluid
- Glass of cold water
6 Steps guide on how to sharpen drill bits
If you are in a rush, no worry, I have got you - watch this simple video below.
Keep reading for more detail.
Step 1: Setup the area and plan your job
This step is often overlooked by even the professional tool operators. Planning is essential when performing a drill sharpening job.
What I typically recommend is that before you go ahead and start your grinding wheel, make sure that all the equipment that you need is available and at hand.
Step 2: Setup your grinding wheel
This step is critical. The most important thing here is that the wheel should move and operate very smoothly without any visible vibrations.
To ensure this, you would typically attach your grinder to your working bench. This will absorb most of the vibrational energy.
If you cannot do this just add dampers under the footing of the machine.
Whichever method you use make sure that the grinder is stable and does not move whilst it is operating.
Step 3: Smooth out the grinding wheel
The purpose of this step, is to remove any microparticles that could have accumulated from a previous job.
If the grinder is new, I would still recommend this step because it practically removes the finishing from the factory and gets the grinder ready for use.
How you do this is by turning on the grinder at full speed and using the head of a nail or a diamond pencil to slowly move back and forth in a horizontal direction across the surface of the grinder.
Do this for about 2 to 3 minutes and that should be enough for you to start your drill.
This step is really important, you will not believe how many people just gloss over it and then get surprised when their drill bits have micro-cracking or do not last as long as they should.
Also if your grinding wheel is equipped and comes with a platform, make sure that you move it as close as possible to the wheel’s edge.
About 1mm is generally more than enough. Anything over a centimeter is typically to far.
It is also a good time to connect your jig to the grinding platform before we start with the drill sharpening.
Step 4: Sharpen drill bit - symmetry
Now that your wheel has been preconditioned and is operating effectively. It is time to sharpen your drill bit. Back to the 3 steps above. Point 1 is to make sure that you have symmetry.
Practically this would be achieved by making sure that you are sharpening at a consistent angle typically between 31° and 45° for both sides.
Then make sure that as you are sharpening move the drill your rotate a bit to make sure the entire heel has been replenished.
Step 5: Sharpen drill bit – Tilt angle
To ensure that there is enough of a tilt angle always move the drill bit in the direction of the rotating wheel as you are smoothing it out. Do not rush, but rather move slowly and smoothly upwards.
The edges will be created. One thing as you are sharpening, make sure to constantly dip your drill bit into water to cool it down. If you avoid doing this you run the risk of your drill bit soften up due to chemical changes at a microscopic level.
Step 6: Post drill and inspection
Once you have followed all the steps above you will need to inspect your sharpened drill bit. Do not expect to get it right the first time simply because it generally requires a lot of practice to perfect.
However there are a couple of things you can do in the beginning to speed up the process.
First is just compare your sharpening work with a brand new drill bit and determine if they match. If not then you will need to go back to your grinding wheel and fix the issue.
Alternatively you can use the parameters below:
- Chisel edge should be about 15% of the diameter of the drill bit if you are going for a 118° sharpening; and
- The rear sharpening edge should be about 7° to 15°, but never lower than 7°.
Final thoughts on how to sharpen drill bits
As you can see, it is not difficult to sharpen a drill bit.
It is also worth noting that there are general guidelines and parameters to follow however it is completely up to you whether you want 118° drill bit, or 90° drill bit.
The ultimate aim is that as long as it has sharp enough round edges, it can definitely do the job.