I remember being alarmed as a boy seeing little sparks coming out of the power drill when my old man let me hang a picture. So why do drills spark?
Power drills have brushed DC motors, and sparking is normal around these while you’re running your drill. However, if the sparks become white, violent, and irregular, or are around the power socket or battery, you could have a problem. If all sparks stop completely there could also be a fault.
Let’s dive down into the subject of sparking drills in greater detail, and look at the difference between ‘good sparks’ and ‘bad sparks’ – and by extension when you need to start worrying and fix your drill…
Are Power Drills Supposed To Spark?
Yes, your power drill is supposed to spark – but only in parts of the drill, and certainly not in a violent way. If your power drill (also called an electric drill) has a brushed DC motor, then sparks are a natural part of its operation.
If you have a brushed DC motor (and we’ll explain the difference between a brushed and an unbrushed in a moment), you’ll see sparks coming from within the unit. These sparks are contained, consistent, and certainly not violent. Sparks around the motor should not be a cause for alarm.
If you see sparks around the battery compartment in a cordless drill, or around the cord in a corded drill, stop using it immediately. These are sparks that are definitely not supposed to happen! Also, as we’ll look at in a moment, the sparks are caused by how the brush in the motor operates; so, if you’re seeing sparks and you have a brushless motor, switch off your drill.
Why Does My Power Drill Spark?
If you have a brushed DC (direct current) motor, it’s normal to see consistent sparks around the motor while you’re running your drill.
Brushed motors are common and inexpensive, and it’s fairly likely that your drill has one. They consist of stationary magnets (called the stator) and a rotating armature that contains an electromagnet (the rotor).
When an electric current is applied to the armature, the rotor spins through 180 degrees. The brushes make contact with the stator, flip the magnetic field, and allow the rotor to spin through 360.
While this is happening, the brushes produce sparks from the electromagnetic charge, and these are visible. Because they occur as part of the drill’s operation, these sparks are regular, and always around the motor. They happen no matter what speed you are using.
Interestingly, if the sparking ceases on a brushed DC drill, that’s when you have a problem. This means that the carbon brushes are wearing out and not operating fully, and it’s time to replace them.
Of course, if you’re drilling metal or composite, you’ll see sparks from the drill bit when it connects with the surface. Again, this is normal, but just be careful that it’s not damaging the drill bit.
If you’d like to know more about how the brushed DC motor works (and see what the inside of a drill looks like), this is a helpful short film about motors.
What’s The Difference Between Good Sparks & Dangerous Ones?
In short, “good sparks” are regular and contained, and happen within an operating brushed DC drill. We don’t need to worry about these.
However, how can we be 100% sure that these sparks are the good guys and not a sign that something’s going wrong? It’s actually easy to spot the difference between safe and dangerous sparks.
Here’s how you can tell that a spark or sparks could be dangerous:
- The sparks are white
- They seem large and sudden or violent
- They are irregular. In other words, they’re not following the brush motion pattern
- The sparks are occurring at the power socket
- They are occurring at the point where the power cable enters the drill
- If it’s a battery-powered cordless drill, the sparks are happening around the battery
In some of these instances, the problem causing the sparking is a simple one to fix. However, it’s definitely a sign that something is wrong. If you see any of the above while drilling (and a damaged battery pack can even spark while not in use), switch the drill off, lay it to one side, and do not use it again until the cause has been investigated and fixed.
Also, please take into account that even though everyday brushed DC drill sparking is normal, a spark is a spark and can cause ignition. Don’t use a brushed DC drill in an enclosed environment where something in the air, like sawdust or gas, could ignite. Switch to a brushless drill that shouldn’t spark.
How Do I Fix My Sparking Drill?
Sparking drills can be easy to fix, but first you need to diagnose the problem. It could be something obvious like a broken cord, or it may be that you simply need to open it up and give it a good old clean. After all, a drill does a lot of messy, dirty work. Brushed DC power drills, in particular, need regular maintenance.
Sometimes, it might be time to say goodbye to your trusty drill. Brushed DC drills are not expensive to buy, and replacing broken parts could be almost as costly as simply getting a new drill. However, here at Take A Yard, we’re all for repairing rather than replacing, provided it’s safe to do so, so here’s a look at some simple power drill maintenance.
Mending The Commutators & Brushes
As we mentioned earlier, the hard-working parts of a power drill can wear out with time. The brushes inside a brushed DC electric drill are made from carbon, and do wear down to the point where they’re no longer long enough to make contact with the commutator (this is the switch that reverses the current direction).
Another problem can simply be that dust and debris have gathered inside the drill and accumulated around the commutator.
If your drill is functioning poorly, open it up and take a look at the commutator and brushes. The most obvious problem will be worn brushes. If they don’t seem worn (they’re still long enough to make contact), remove them and gently clean them with fine-grit paper.
If they’re worn, check which size fits your drill, and order a new set. While the brushes are out of the drill, you can clean the commutator. This can prevent excess sparking caused by dirt build-up, as well as helping it to run more effectively.
You’ll need more of that fine grit paper plus an electronic contact cleaner spray (easy to buy in Walmart, Amazon, Home Depot and so on). We recommend gloves and protective goggles, and you’ll need a fine brush like an old toothbrush or artist paintbrush.
Take photos as you go along: this makes sure that everything goes back exactly where it should (and you can impress your friends with the illustrated tale of your fixing skills).
Making sure you’re in a ventilated space, spray the contact cleaner onto the commutator. Using the brush, carefully clean off any built-up debris.
Next, sand the commutator using the fine grit paper. Clean away any sanding debris (you may need something like a plastic scriber to get this out of the commutator’s slots).
Fixing Other Drill Problems
Worn or dirty brushes and a dust-covered commutator are common problems with the brushed DC drill. However, it could be something else that’s causing the sparks.
If you have noticed sparks around the cord (at either end) or that there appears to be damage to any part of the cord, you’ll either need a new cord or a new drill. Check the warranty with your drill; however, this is one of those occasions when a new drill may work out as a cost-effective option.
Do you have a cordless drill? If there are sparks coming from the battery, disconnect it and clean it, as it could be dirty contacts that are causing the problem. If the contacts appear clean, this is clearly not the problem, and the safest approach is to get a new battery.
In the case of dirty-looking contacts, clean them, then cautiously try the drill again. If there are still sparks from the battery area, switch off the drill and replace the battery before using it again.
Why Does My Drill Smell Like It’s Burning?
Have you noticed a burning smell when you’re drilling? This could simply be hot dust, but it might be a sign that something isn’t working. Stop using the drill, switch it off, then start the diagnosis: never assume it’s “just dust”.
It’s very likely it is dust. The brushes cause dust, and as we’ve just discussed, dust and debris accumulate around the commutator. The burning problem may be solved just by cleaning inside the drill, as described above.
Having talked about cleaning inside the drill, cheaper models can’t always be opened up, checked, and cleaned. If yours doesn’t come apart, we’re sorry, but a burning smell means it has to go, and you’ll need a whole new motor or even drill. If you can, next time get a model with an accessible motor.
The burning smell could also be caused by your drill working too hard. It could be that you’re using a drill that isn’t powerful enough for your needs. Take a look at this guide to choosing the right power tool for the job.
A certain amount of sparking when using your power drill is perfectly normal – these are what we call ‘good sparks’.
However, if you see some of the tell-tale signs of ‘bad sparks’ as outlined in this article, then it’s time to act and clean your drill.
In fact, just to be more safe than sorry, it’s advisable to perform regular maintenance on your drill anyway – so you can be sure that all the sparks you see are always ‘good’ ones. 🙂
Homeowner and property investor Larry James founded Take a Yard in 2020 to bring you the very best outdoor living content, based on his years of experience managing outside spaces. Read more >