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 the better performance of the drill bit.
1. Improper Drill Bit Cutting 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 manufacture 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, 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 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, 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, drilling wet wood, and using less-density flute drill bits.
In order to prevent this, you must keep 2 times drill bit diameter flute length from the top of the drill. So removed chips can be moved out easily. As well as you can use 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.