Why Does a Drill Bit Hot: Reasons and Solutions

A drill bit is hot due to these 9 major reasons such as using improper drill bit cutting edge and angle, using a wrong drill bit, using a high RPM for drilling, applying more thrust on the drill bit, drilling with no cutting oils, and inner clogging due to swarfs.

If you are not able to reduce heat generation on the drill bit, it can be overheated. As a result of drill bit overheating smoke can rise, burning marks can appear on the drilling surface, the drilling hole can be not cylindrical, and finally drill bit can be broken easily. Hence, you should control the drill bit heat generation for better drill bit performance.

1. Improper Drill Bit Cutting Angle

118 and 135 drill bit angles
Right Drill Bit Angle

Improper drill bit cutting angle can heat up the drill bit due to slippering on the drilling material. Slippery drill bit can produce more heat due to friction while it is rotating. Hence drill bit should have a recommended cutting angle for the materials.

Normally, soft materials such as wood and aluminum need a 118-degree cutting angle, and hard materials such as cast iron need a 135-degree drill bit. If there are wrong drill bits, it will take much time, and both drill bit and drilling machine can be heated more and more. If there is no proper cutting angle, you should sharpen it properly.

If your drill bit is already hot you can use these 07 Tips to Cool the Drill Bit.

2. Blunt Drill Bit Cutting Edge

When the drill bit cutting edge is blunt, it will not cut the material while the drill bit is rotating. Instead of cutting, it will slip on the material surface. This will produce a lot of heat due to the friction, and the result will be an overheated drill bit.

A sharp cutting edge of the drill bit can be damaged due to abrasion, meeting harder material in the drilling material, and using the wrong drill bit for the materials. Hence, the drill bit should be sharpened according to the recommended drill bit angles.

3. Select a Wrong Drill Bit

Selecting the wrong drill bit for the specific material will be affect badly to the drill bit. If the drill bit hardness is less than the material hardness, the drill bit can be heated too much. Hence, you should consider the drill bit hardness, geometry, coating, and manufacturing material before using it for the materials.

When you drill any material, it should be lower in the Rockwell C hardness scale than the drill bit hardness value.

4. Drill Higher RPM

When the drill bit RPM is high, it touches the surface at a higher rate. Due to this, the drill bit can be heated and the result is an overheated drill bit. Hence, you should use the recommended RPM and feed rate for the drilling materials.

Normally, wood drilling requires high RPM, and steel, concrete, stone, brick, and glass require less RPM. When the drilling material is tougher, its heating amount is high.

5. Apply Too Much Thrust on Drill Bit

Applying too much thrust on the drill bit will increase the feeding rate. As a result of this drill bit produces more heat and torque. Hence drill bit can be broken easily due to the increase of the torque of the drilling machine. Hence you should not thrust much into the drill while the chips are removed in a gentle way. That is the sufficient force you should apply to the drill.

You can observe the too much thrust on the drill bit by its smoking. If there is any smoking on the drill bit, you should reduce the thrust on the drill bit and reduce the RPM.

6. Lack of Cutting Oil on the Drill Bit

Lack of cutting oil will increase the friction between the drill bit and the material and reduce thermal conduction. As a result of this, the drill bit can be overheated, and then it can break.

Cutting oil acts as a lubricant for the drilling task and heat conduction media. Hence, cutting oil can reduce the friction between the drill bit and the material and transfer the generated heat from the drill bit. Both of these tasks reduce the drill bit heating.

Can I Use Water as Cutting Fluid?

Water can be used as cutting fluid for the glass, tile, and concrete drilling process to prevent dust and improve thermal conduction. But it can not be used on wood and metal. Because water boils at 100 °C, and there are no lubricant properties. When water is used for a long time, there will be rusting due to interaction with the atmosphere. Due to this, water can’t be used as a cutting oil for steel.

7. Drilling in Higher Temperature Areas

Drilling in higher-temperature areas or high-temperature workpieces will reduce the thermal conduction due to outer temperature. Hence, the drill bit can overheat easily. As a result of this drill bit will be damaged easily. Using cutting oil, you can avoid this, and changing the drill bits continuously will be a successful solution.

10. Chips Clogging Inside the Drilled Hole

If there is no sufficient flute length, drilled chips can be clogged between the drill bit and the drilled hole. As a result of this, friction can be increased, and the drill bit will be overheated quickly. As a result, the drill bit can be broken easily.

Chips can be clogged when there is no cutting fluid, when drilling wet wood, and when using less-density flute drill bits.

In order to prevent this, you must keep 2 the drill bit diameter flute length from the top of the drill. So, removed chips can be moved out easily. You can use the push-and-pull drilling method with a lower RPM.

7. Drilling Soft and Hard Combined Materials

If there is harder material inside the soft material drill bit can be damaged due to contact with the harder material. As an example when we drill into the wood, there may be part of the nail inside. When the mail is hit with the wood drill bit, it can be damaged because wood drill bits are not designed for drilling metals.

How to Prevent Drill Bit Over Heating?

A hot drill bit can be overheated if you use it under the same conditions. You can prevent drill bit overheating by following the below 6 ways.

  1. Using cutting fluid for drilling – Cutting fluids is essential in preventing drill bit overheating. These fluids lubricate the drilling surface, reducing the friction that can cause heat. Additionally, they also help in cooling the drill bit and the workpiece, preventing overheating.
  2. Reduce the drilling speed – Over-speeding can cause the drill bit to overheat. By reducing the drill speed, you allow the drill bit to cut at a steady pace, reducing the chances of overheating. It is important to adjust the speed according to the material you are drilling.
  3. Select a proper drill bit – Using the right drill bit for the right material can prevent overheating. Harder materials require harder drill bits. Using a softer drill bit on a hard material can cause the drill bit to overheat and wear out quickly.
  4. Regular breaks during drilling – Regular breaks during drilling can help to prevent overheating. This allows the drill bit to cool down before you continue with your drilling.
  5. Use a sharpended drill bit – Using sharp drill bits can also prevent overheating. Dull drill bits create more friction and thus more heat. Regularly sharpening your drill bits can help to reduce the heat produced during drilling.
  6. Apply proper pressure on drillbit – Applying the right amount of pressure is crucial in preventing drill bit overheating. Too much pressure can cause the drill bit to work harder, leading to excessive heat. On the other hand, too little pressure can cause the drill bit to rub against the material, generating heat through friction. Finding the right balance is key to ensuring your drill bit doesn’t overheat.

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.

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