Why Do Drill Bits Break? – Top 09 Reasons and Solutions!

Drill bits can be broken due to these reasons such as selecting the wrong drill bit, manufacturing faults, clogging the swarfs, not using cutting oils, applying too much thrust, drilling in high RPM, use improper drills and drilling bits. These reasons are mainly affecting any drill bit breaking.

Drill bits are made for the specified task. There are masonry bits, wood bits, and steel bits. These are specified for special material and recommended tool settings. When you misuse them for the wrong usage, it can be broken. So let’s see in detail why drill bits break and how we can prevent it.

01. Manufacturing Faults

Drill bits are made with many combined materials. When they are manufactured and sharpened, some cracks and faults can occur easily.

In the modern market, there are cheap and low-quality products. Those are made with low-quality materials and technologies. If you use it in order to cut the budget, you may face many problems. So when you select a drill bit, make sure it is from a well-known brand.

02. Wrong Drill Bit Selection

This is a really common problem. When we are working, we may not pay much attention to all facts. Sometimes we try to drill concrete with a wood drill bit.

At that time, it can be broken easily. There are types of drill bits according to material, coating and geometry. You can choose the proper drill bit by using the below details.

Low Carbon Steel – Suitable for wood

High Carbon Steel – Used both wood and metal.

High-Speed Steel Drill Bits – These bits can be used to drill metal or hardwood. Materials that are not able to be cut using the high-carbon steel HSS is used.

High-speed Steel with Cobolt – Drill stainless steel and more drilling strength than HSS

Carbide Drill Bits – Used for stone, Bricks, concrete, metals, woods

Polycrystalline Diamond Drill bits – These are used to drill tiles, stones, and glasses.

03. Swarf Clogging

Drilling is a cut-and-removing process. Removing debris is called chips or swarf.

These swarfs removing rate depends on the cutting speed. Due to high-speed drilling, those are generated highly. If any problem occurs to clog inside, inner friction can be increased, and tool temperature is increased. Hence drill bit can get hot. And finally, drill bit can be broken. You can cool the drill bit using these methods.

Swarf generate from drill bit
Proper swarfs removing

When you drill, make sure to keep the space to remove the swarf. Normally keep free two times the diameter from the top of the drill bit. That means do not drill until flutes are not showing to you. There should be a safe space to remove the swarf from the drilling hole. If you drill wet wood, you can see, the swarf is always clogged due to wet conditions. You can remove them while you are drilling.

When you drill, do not apply the same force constantly. Thrust and release it and pull a bit out. In this process, swarfs can be removed easily.

04. No Cutting Oils

When you drill metal, you should use cutting oil. Drilling is a heat generation, frictional process. Hence it needs lubricants or cutting oils to lubricate the drilling process and remove the generated heat. Because of this, you must use recommended cutting oils.

Without cutting oils, tools and materials can be heated more and more. Due to this, tools can be broken easily. When you use cutting oil, you can see chips are removed smoothly, and there are no internal cloggings. Due to this reason, you can drill fast.

05. Apply too Much Thrust

Thrust is needed for the drilling process. We have to apply force to the drill as the drill bit penetrates the material while it is cutting. So when you apply more thrust, it can’t bear the drill. The drill required more power. So speed is reduced and torque is increased. This kind of torque will break the drill bit easily.

When we force more, the temperature is also increased due to high friction. You can apply force until chips are constantly removed. Do not thrust more while swarfs are removing perfectly. That is the maximum cutting speed that you can reach.

06. High-Speed Drilling

Normally wood is required high RPM for drilling, and metal and concrete required lower RPM for the drilling process. If you get used to drilling at high speed in the metal, the drill bit can be heated much due to friction. This will be a reason for breaking the drill bit easily.

Most of the drill bits are broken due to this reason. You must use recommended drilling speed for each material. This can be varied with the products. Some products can use at high speed. But most are not. You can use this table for wood, brass, aluminum, and steel drilling RPMs for twist drill bits.

Twist Drill BitsSoft WoodHard WoodAcrylicBrassAluminiumSteel
1/16″ to 3/16″3000 RPM3000 RPM2500 RPM3000 RPM3000 RPM3000 RPM
1/4″ to 3/8″3000 RPM1500 RPM2000 RPM 11200 RPM 2500 RPM1000 RPM
7/16″ to 5/8″1500 RPM750 RPM1500 RPM750 RPM 1500 RPM600 RPM
11/16″ to 1″750 RPM500 RPMNR400 RPM 1000 RPM350 RPM
Twist drill bits and recommended RPMs for wood and steel

When you use different drill bits, you can download the chart here.

Read More About – Drill Feed and Speeds

07. Combinations of Different Materials

Some nails deeply penetrate the wood. And some can be a break as one part inside. When you drill such a place, your drill bit can easily break due to the inside nail part. So you had better pay your full attention to the drilling material. If that is old wood, check carefully to avoid this kind of problem.

When you drill into concrete, you can observe this. Concrete includes steel to increase tensile strength. So when you drill, there is steel inside.

If your drill bit is not designed for Both materials, do not continue the work. Use any bar cutter and then drill it again. If you use SDS max drill with the proper drill bit, you can drill both together.

08. High Temperature

Temperature is really negative effect on the drilling process. While you drill a high-temperature area, you can observe the produced temperature is not transferred properly. Due to this, the drill bit and drill also overheated, which can be broken easily. In this situation, cutting oil will not transfer the heating out, so heating up and damage can occur.

Normally coated drill bits are highly resistant to heating and abrasion. Hence you can use coated drill bits when you drill such kinds of materials.

Read More About – Top 08 Drill Bit Problems and Solutions

09. Use Improper Drill Bits

a blunt drill bit
Blunt drill bits Image source

If your drill bit is not sharpened and there is no proper cutting angle, you cannot drill in a proper manner. If there is no proper cutting angle drill bit will be slippering and produce more heat. This heat can break the drill bit. Sometimes wood drill bits are damaged due to inside nails, and its cutting path is damaged seriously. You can observe its swarf are not out properly.

Properly sharpen drillbits produce 1″-2″ swarfs outside the drilling hole. So immediately sharpen the drill bit with proper angles.

You must maintain the below angle in the drilling process.

118 Degree- Softmaterial like wood and aluminum
135 Degree – Hard material like stainless steel


Tom Mackency

Tom Mackency

Hi, I am Tom Mackency. It has been 10 years that I have been working as a professional woodworker since 2013. I am really enjoying my carrier by creating many kinds of projects in my workshop. But mostly I like for home improvement projects. Home improvement and DIY projects are the most interesting things for me. More than that, the coolest things are power tools. Those are very precious and efficient than a decade ago. So I try to introduce so many things about power tools, woodworking, DIY projects, home improvement and many more interesting topics here.