Drills are common household power tools. For novices, it may be unclear if they can overheat.

The simple answer is yes. Drills can overheat for a number of different reasons. The first thing to do once it happens is to let it cool down. Then, determine what caused it to see if it could be part of a larger issue.

If you would like to know about the factors that can lead to overheating, what to do if it does overheat, how to prevent it and what drills to avoid, then continue reading!

Factors That Affect Overheating

Here are a few factors that may lead to overheating:

• It may be running for too long. The motor generates heat and when it is overworked, the drill can become very hot.
• The motor might be faulty. If it is unclear on the cause, it might be the motor itself. It may be time for a new drill.
• If it is a brushed motor, the brushes in the drill have been worn down. They usually wear down after long, repeated use and can cause a lot of friction by being in constant contact with the motor, which will generate a lot of heat. It is easily replaceable, but it might be beneficial to have a brushless motor power drill. 
• Amount of pressure on the drill. Putting too much pressure on the drill can lead to a dull drill bit. The same can be said with too little pressure.
• Drill bit is blunt. When this happens, too much friction builds up and the drill will overheat.
• Something is blocking the drill’s air vents, if it has them. It could be anything from dust to your hands blocking them.
• The age of the drill. As with most products, the older the drill, the more likely it is to lose its functionality. At this point, it may be time to replace it.
• The brand of drill. Some brands are more susceptible to overheating. Continue reading to find out which brands to avoid!

What to Do if it Overheats

First thing is first: let it cool down!

The next thing to do is to determine what caused the overheating. If there is not a clear answer and you do not feel comfortable disassembling and reassembling the drill to find out, it may be safer to take it to a repair shop and they can determine the cause for you.

For those of you who want to “DIY-it”, here is how you disassemble your drill:

If it has a dull drill bit, do not disassemble the drill and skip to Step 8.

• • Step 1: For cordless drills, remove the battery first by pressing the battery release button.
  • Step 2: Unscrew and remove the outer shell of the drill. Check for any damaged parts.

If it is the motor brush, continue to Step 3. If it is neither the drill bit nor motor brush, skip to Step 15.

• • Step 3: If you have a brushed motor drill and you notice that the brushes on the motor are worn down, do not worry! It is an easily replaceable component. All you have to do is buy the appropriate brushes for that drill and replace them yourself. They look like this: →
  • Step 4: Remove the clips that hold the brushes in place. Remove the old brushes.
  • Step 5: Replace with the new brush.
  • Step 6: Re-attach the clip to its proper place. Once you have replaced the brushes, reassemble the drill.

If you have a chuck key for your drill, skip to Step 11. If not, continue to Step 7.

• • Step 7: To replace the dull drill bit on a keyless chuck, loosen the chuck, which holds the drill bit. Turn it counterclockwise.
  • Step 8: Remove the damaged drill bit. Replace it with a new one using your thumb and index finger.
  • Step 9: Make sure to keep holding on to the drill bit. It is not secured into place yet.
  • Step 10: Keep lightly holding on to the bit while you tighten it into place. Squeeze the trigger of the drill slightly and in short bursts until it is secure.
  • Step 11: If your drill requires a chuck key to loosen the chuck, insert the chuck key. Line up the teeth of the chuck key so that they match with the teeth of the chuck.
  • Step 12: Turn the key counterclockwise. Once the chuck is loosened, remove the bit using your thumb and index finger.
  • Step 13: Insert a new bit that is neither dull nor damaged. While holding the bit, tighten the chuck using the chuck key.
  • Step 14: Remove the chuck key and your hand. Check that the bit is secured properly in the drill by squeezing the trigger.
  • Step 15: If it is neither the motor brush nor the drill bit, it might be a more a serious issue, such as the motor itself, which might not be as easily replaceable.
  • Step 16: If that is the case, close up your drill and take the drill to a repair shop, such as a local hardware store or a Home Depot, who can better diagnose the problem and provide a solution.

How to Prevent it

One simple way to ensure that the drill does not overheat and does not dull the drill bit is to make sure that the pressure applied while using it is consistent.

You want to be firm with your pressure, but you do not want to apply too much as to cause undue stress on the drill. You also do not want to be too light with your pressure. If you are too light, there is the possibility that the drill could run away from you and you lose control of it, which will also dull the drill bit.

Along with firm pressure when holding the drill, a rule of thumb is to have the drill on a slower speed when you are using it.

Drills can come with pressure-sensitive triggers. The harder you squeeze the trigger, the faster the drill bit will turn. It is always safer to have it on a slow and steady setting as opposed to the fastest, which can cause overheating if used for an extended period of time.

Another way to ensure that the drill does not overheat is the use of cutting oil. Cutting oil serves as a lubricant to reduce friction and heat buildup for the drill.

Not only does it prevent overheating, but it increases the lifespan of your drill bit and prevents fractures in the material. All you have to do is determine the type of cutting oil that is appropriate for your machine and apply it to your drill bit.

There are many different types of cutting oils:

• • • Liquids
      • Synthetic
      • Semi-synthetic
      • Mineral
    • Pastes or gels
    • Aerosols
    • Carbon Dioxide Coolants
    • Compressed Air

When looking at the different types of cutting oils, please take into consideration what you are using the drill for (i.e. drilling holes in metal, in wood or tightening screws, nails, etc) as different cutting oils are more effective with different materials.  

If you are drilling holes in metal, cutting fluids, such as TAP-MAGIC for steel iron and ALUM-TAP for aluminum, prove to be effective lubricants as long as the drill is in its slow setting. It is also best to research the type of metal you will be drill into as well.

Please be careful when applying the cutting oils as they may contain harmful chemicals that could cause injury if you were to come into direct contact with them.

What to Avoid(Types of Drills That Will Overheat)

There are a few things to consider when choosing your drill.

• • • The Reviews/Brands
    • Overheating protection mechanism in place
    • Cordless or Corded
      • Battery Power Type (Lithium-Ion vs Nickel-Cadmium) if Cordless
    • Brushed or Brushless Motor
    • Variable Speed or One Speed
    • Torque/Power (Voltage)
    • Use of the drill: Common household projects or larger projects

Avoid drills that are cordless, brushed motor, one-speed, low-voltage, and that lack an anti-heating mechanism, if you are looking to take on larger projects and do not want the drill to overheat.

Drills, as a fail-safe, should have a mechanism in place that detects when the drill is getting too hot. A test was done using the Makita Brushless Hammer Drill, during which the drill itself started smoking from overuse.

When purchasing a power drill, make sure to look for protection mechanisms for overheating, whether it be a cooling system or a switch that turns the drill off once it starts to get too hot. The Makita Brushless Hammer Drill did not have that and therefore, resulted in smoke.

Another factor that can affect heat is whether or not the drill is corded. Cordless or corded drills have pros and cons attached to both. As a general consensus, corded drills have more power or torque than cordless drills. They also tend to be lighter because there is not a heavy battery attached.

Cordless drills, on the other hand, can be large and bulky.

They can come with different types of batteries, most commonly lithium-ion or nickel-cadmium. There are varying reviews for the lifespan and functionality of these batteries. However, the lithium-ion battery tends to be lighter, longer-lasting, but more expensive than the nickel-cadmium batteries. When lithium-ion batteries overheat, they can become flammable, so beware and make sure to let the battery cool down before doing anything else.

Nickel-cadmium batteries may be the older version of lithium-ion, but they can last longer and will not overheat if used properly. If you are using a cordless drill that has a nickel-cadmium battery, make sure to completely drain the battery of power before charging it back up again. Reviews suggest waiting until you are about to use the drill again before you charge it.

In my opinion, I would avoid using the lithium-ion batteries, even though they are more common, because they are not as heat-resistant as nickel-cadmium and they are more expensive.

If you use the nickel-cadmium batteries right, they can last you a long time without overheating.

Other than batteries, another aspect that can affect overheating is whether or not the drill has a brushed motor. As mentioned earlier, the brushes around the motor can cause friction when the motor is turning. To avoid that altogether, it might be safer to go with drills that have a brushless motor.

You also want to make sure that you can control the speed and power of the drill.

The higher the speed on the drill, the hotter the drill will get. This is where variable speed comes in.

Cheaper models of drills tend to have only one speed. These drills are at “top-speed” when they are on. There is no way for you to control how fast the drill bit is turning.

Variable speed allows you to control that with how much pressure you put on the trigger. The harder you squeeze the trigger, the faster the speed of the drill.

Another factor in speed is the voltage. The higher the voltage of the drill, the more power it will have and the bigger projects it can handle. Eighteen volts tends to be the average voltage for common household projects.

In 2015, the US recalled 1.5 million Drill Master 18 Volt Cordless ⅜ inch drills for overheating to the point that customers reported burns on their hands. These drills are sold relatively cheap at Harbor Freight Tools. They are specifically designed for small projects only and are not equipped to take on big tasks.

Another brand that has been reported to overheat and jam are the Black and Decker corded drills. Similar to the Drill Master brand, Black and Decker are on the cheaper side and are only really functional for around-the-house projects.

If you are a career power tool user, then you might want to invest in a drill that is a little more sustainable for the types of projects that you will take on.

Hopefully, you found this helpful in choosing what to do if your drill overheats and what you can do to prevent or avoid it.