How to Fix a Miter Saw That is Sparking?

Why your miter saw is sparking?

The reason your miter saw is sparking is because of a shorting-out armature that is destroying the coils or a worn-out bearing. Worn carbon brushes or damaged cap brushes is another reason your miter saw is sparking.


miter saw sparking


Shorting out Armature

The part of the miter saw that generates power is referred to as the armature. It is made up of windings or coils. Because of the magnetic field, the coil may move due to the current of electricity flowing through it. The armature is capable of rotating at a high rate per minute. However, there is a possibility that the armature on the inside will short out. The coil has a tiny coating of rubber wrapping; if that layer is ever destroyed, the coil may experience an internal short. This lets your miter saw produce a powerful spark.


Worn out Bearing

A bearing is used to secure one facet of the armature shaft in place. Bearings are not designed to last a lifetime. It can damage owing to misalignment, unbalance, looseness, friction, etc. Sparking can be seen at the end of the armature shaft if the bearing is broken and needs to be replaced.


Worn carbon brushes

The carbon brushes most often cause the sparks coming from the miter saw. Hard carbon is the primary component of carbon brushes. It is capable of conducting electricity and supplying the armature with electrical power. Carbon brushes are in contact with the commutator when the armature is rotating.

Surface temperatures have increased due to the high-speed spinning, and sparks may be seen. Some miter saws typically come equipped with a light spring. This is not something that should be visible from the outside. It becomes obvious when the carbon brushes have reached the end of their usage.


Damaged brush caps

You may have seen brush caps when using a miter saw. Brush caps are needed to simply repair or replace the miter saw brush. In that case, you will need to remove additional nuts and screws attached to the miter saw motor. It requires a lot of effort. If the brush caps is damaged, the tightening mechanism will not function properly, and you will position the interior brush incorrectly. Consequently, sparks can be seen around inside the motor.


How to fix a miter saw that is sparking?

You can fix a sparking miter saw by cleaning the armature, replacing the bearing, and replacing the carbon brushes.


Cleaning the armature

The part of the motor that generates power is called the armature, which may be found inside the field. If the armature is shorting out, it will cause significant sparks, and if it is not addressed, it might lead to more issues. Follow this guide to change your armature.


  1. Take off the belt cover and remove the belt from the pulleys so you can check the state of the armature. On some models, a sliding bracket may be held in place by screws; if this is the case, you should release the screws.
  2. Remove the belt after releasing the tension using the screw in the back of the device. Then, remove the end cap from the motor, then slip the tension spring into place.
  3. Now, take the brushes out of the case. Some versions have brush caps on the side of the device, and to remove the brushes, you can pull off the brush cap using a screwdriver.
  4. First, take off the bracket for the dust bag, then take off the housing for the armature on the saw.
  5. To prevent the armature shaft from being damaged, you should only use a rubber mallet or a brass hammer to gently tap the end of the armature free of the housing.
  6. Use just an electrical contact cleaner to clean the armature, then wipe it dry afterward. If there are burn scars on the armature, you should replace them. The presence of burn marks is an indication of sparking and a defective armature.


Replacing the bearing

If a bearing becomes stuck, it will impose stress on the motor, resulting in the motor sparking more than normal. Bearings are unique to each model, thus, the repair processes for each bearing will be unique, but the techniques for repairing other parts will be consistent. Follow these steps to replace the bearing.


  1. To inspect and perhaps replace the armature bearings, you must remove the belt cover, and then the belt must be walked off the pulleys. On some versions, a sliding bracket may be held in place by screws; if this is the case, you should release the screws.
  2. Remove the belt after releasing the tension using the screw in the back of the device.
  3. Certain versions feature brush caps on the side of the device to gain access to the brushes and remove them. These brush caps are simple to remove with a screwdriver.
  4. Take off the end cover of the motor, shift the tension spring over to the other side, and then take out the brushes.
  5. First, remove the bracket for the dust bag, and then remove the armature housing from the saw.
  6. To prevent the armature shaft from being damaged, you should only use a rubber mallet or a brass hammer to gently tap the end of the armature free of the housing. To identify which of the bearings on the armature shaft is malfunctioning, spin all of them.
  7. Remove the pulley screw to access the bearing next to the fan. To dislodge the pulley’s position on the shaft, heat it with a heat gun.
  8. Using a small screwdriver, pry out the retaining ring by working it up the shaft in a clockwise direction. Avoid causing any damage to the fan.
  9. To change out the other bearing on the armature shaft, remove the old bearing from the shaft with the assistance of a bearing puller.
  10. Next, put the new bearing on the shaft with the assistance of a socket that only makes contact with the bearing’s inner race.
  11. Make it secure by tapping it with a hammer.
  12. Place the armature within the housing by sliding it in. When you set the bearing into the motor housing, use only a hammer to tap on the pulley screw. This will prevent you from harming the armature shaft.
  13. Put the motor component back on the miter saw where it belongs. Replace the end cap on the motor as well as the brushes. First, the dust bag bracket should be reinstalled, followed by the belt and the belt cover.


Replacing carbon brushes

Because they are mounted on the commutator, the carbon brushes can deliver energy to the armature. The brushes will eventually become unusable due to wear and tear. When this happens, they will emit more sparks than they normally do, and it will be necessary to replace them. Here are steps to follow to replace your carbon brushes.


  1. Take off the end cap of the motor and look at the carbon brushes to see how well they are holding up.
  2. By tugging the spring to the side with needle-nose pliers, you can release the tension applied to the springs.
  3. Remove the carbon brushes from their holders. It must be changed if the brush length is 1/8 of an inch or less. It is also a good idea to clean the commutator if the brushes have been worn out and need to be replaced.
  4. Remove the screws used to attach the armature housing to the miter saw, and pull it in the other direction. Only clean the commutator in the direction of travel using aluminum oxide sandpaper with a grain of 600.
  5. Utilizing a plastic scribe, clean the spaces in between the commutator bars. Use only an electrical contact cleaner, then wipe dry after you’re done.
  6. Put the armature casing back on the miter saw and secure it.
  7. Replace the brushes, readjust the tension, and reconnect the motor cap before testing the motor.


Why your miter saw is sparking from the motor?

Your miter saw is sparking from the motor because the carbon brushes in your motor have gone bad or your commutator is too dirty. A shorting out field is another reason your miter saw is sparking from the motor.

If the brushes on your motor are sparking, this could indicate that you need to replace them. A certain amount of sparking within a tool is expected; however, if it worsens, it is probably a sign that the carbon brush is wearing down.


You can check the air vents while using your tool to monitor the sparking it produces. This allows you to determine how much the sparking has changed throughout its lifetime. Check to see if there is a carbon brush cover that is not securely fastened or if there is an excessive amount of dirt or other debris in the mechanisms. This could prevent the brushes from functioning properly.

If there is excessive sparking, also known as arching, this could be a sign that the carbon brushes are not making good contact with the commutator (the copper segments). This indicates that there is a risk that the commutator is wearing out. You might need to replace the armature if a professional tool repair specialist determines that this is the problem after examining it and diagnosing it.


Suppose upon inspection of your carbon brushes; you discover evidence of cracking, crumbling, or burning. In that case, it is strongly recommended that you replace the armature as soon as possible because changing the brushes won’t assist in this situation. Broken lead in the spring is likely the cause of any discoloration on the spring, such as a rainbow pattern; this indicates that the spring needs to be replaced.

If the spring has deflated, you will most certainly need to purchase a new brush. It is not a good idea to keep worn brushes in a tool for an extended period since they can cause damage to the armature, which is very costly to repair.


Why your Ryobi miter saw is sparking?

The reason your Ryobi miter saw is sparking is because there is something unusual obstructing the blade or worn carbon brushes. Fields shorting out is another reason your Ryobi miter saw is sparking. Here are steps to fix your Ryobi miter saw.


  1. When too much grease or oil is applied, it can cause the substance to spread throughout the engine. Because of this, there is a possibility that some dust particles will become adhered to the interior surface. This is a surefire way to start a fire.
  2. Regular maintenance and troubleshooting of the Ryobi miter saw comes in at number two on the list of most critical things. When repairing something, you should clean the commutator, apply oil and grease to the appropriate spots, and so on.
  3. When the length of the carbon brushes reaches one-fourth of their initial length, you are required to replace them.
  4. In a perfect world, when a part is fixed, you should do it correctly. If you attempt to fix the pieces incorrectly, for instance, by using an uneven bearing, you will cause them to wear out faster. Because of this, there is a possibility that sparks will fly after a certain number of times.

Therefore, it is best to follow the instructions from your model to avoid sparks when using the miter saw.


Why your Dewalt miter saw is sparking?

The reason your Dewalt miter saw is sparking is because your armature is shorting out, thereby producing more sparks, or your bearing has seized, putting a strain on your saw. Your brush caps being broken is another reason your Dewalt miter saw is sparking.

You should know that sparks and smoke are often created by brushes worn out. Brushes will eventually become worn out over time and require replacement. Although it is impossible to completely prevent wear and tear, you can surely slow down the process. Here are steps to help you extend the life of your miter saw brushes and reduce the number of times it sparks.


  1. First, check to see if the miter saw blade you are using is adequate for the material you are cutting. In addition to that, make sure that this blade is spotless and razor-sharp. This will help to ensure that the miter saw can cut through the material without difficulty and that it will not have to strain to perform the cut.
  2. Second, when cutting something, ensure that you give the blade enough time to go up to full speed before making contact with the substance. A sharp blade makes cutting easier and quicker. A simpler cut will result in less wear.
  3. Third, inspect your blade frequently for any buildup or filth. Even while the blade is still sharp behind the layer of filth, it may become dull over time due to sap or other types of composite materials that build up on the blade.
  4. Check if your carbon brushes are in good shape. If not, replace them immediately to avoid future sparks from your Dewalt miter saw.
  5. Always have regular maintenance on your miter saw as this will prevent future problems.