Miter saw grinding noise

A miter saw is a vital tool found in most workshops as it helps carpenters and woodwork experts in the easy and swift cutting of wood. They are craftily engineered to be robust and to give the desired level of service to the users.

However, it can be disturbing and uncomfortable when a miter saw starts making grinding noise. As a novice, it may be challenging to troubleshoot and get to the bottom of the issue. Although it is normal for miter saws to make noise while in use, grinding noise may indicate an issue with your armature, brushes, or both.

Due to the continuous use of your miter saw over time, the worn-out brushes are prone to chipping, and the chip may become wedged, thus causing the grinding noise. Regular maintenance and replacement of worn-out components of the miter saw is essential in ensuring that your power tool is in good shape and increases its lifespan.

When your miter saw starts making grinding noise, you should get it repaired in order to resume your regular woodworking duties. To address this issue, replacement of the brushes is recommended. Although the brushes are designed to last long, they may get worn out regularly due to rigid woodwork undertakings.

This piece will enlighten you on the reason behind the grinding noise made by a miter saw and on how to address the issue.

Let’s get to details.

Table of Contents

What Causes a Grinding Noise in a Mitre Saw?

Like any other heavy-use equipment, miter saws fall victim to tear and wear, electrical issues, and malfunctions. Even when the best power tool maintenance is adhered to, miter saws can fail to work optimally and require immediate scrutiny and possible repair. When your miter saw makes a squealing and grinding noise, then you should know that the carbon brushes, the bearings, and the armature of your miter saw have malfunctioned. Thus you shouldn’t take the issue lightly, and you should seek the means to fix it.

The grinding noise made by your miter saw is a red flag; thus, a diagnosis should be conducted to determine the problem and the next course of action. Malfunction in the following parts of the miter saw would be the reason behind the uncomfortable noise:

  • Miter Saw Bearings

When the bearings of your miter saw become worn out, they can make the grinding or squealing noise. In some scenarios, it can also cause vibration. When a bearing that is seized spins in its housing, it ends up causing the grinding noise. To fix this issue, you should replace the bearings of your miter saw. You should first start by separating the case into two by removing the screws. On some other miter saw models, you may be required first to remove the front gear housing to access the bearings.

You will then be required to remove the carbon brush holders swiftly by pulling them up by a wire. Remove the spindle assembly and the chuck. The motor is then lifted, and the armature is placed out of the field. Depending on the model of your miter saw, to raise the motor, you will need to unplug the electrical connectors.

To determine if the bearing is in good shape or not, spin it and listen for roughness. Using a bearing puller, remove the damaged bearing. You are then required to install a bearing separator and put the separator on a bench vice on the bearing. The bench vice should be opened enough to the exact point where the bearing separator makes contact. You can then use a hammer and a punch to remove the bearing.

After removing the damaged bearing, install the new one on the shaft through the use of a socket that makes contact with your miter saw bearing race to ensure it does not damage. Using a hammer, tap it firmly in place. After completing the repair, you should put the armature back in its field and reinstall the chuck assembly and spindle back in the case. If your miter saw the brush holders are in good shape, reinstall it using a small screwdriver to grip the brush down. Replacing the malfunctioned bearing will get your miter back in good condition and won’t produce the grinding noise.

  • Miter Saw Carbon Brushes

If one of the brushes of your miter saw breaks off and becomes wedged between the housing and the commutator or any part of your miter saw, it produces the squealing and the grinding noise. Once you have made the diagnosis and determined that the brushes are the cause of the malfunction, it would be best if you separated the case into two using a screwdriver. By pulling them by a wire, gently remove the brush holders.  Scrutinize the brushes to determine if there is any breakage. If there is a piece of the brush missing, you should replace it with a new one to restore your miter saw back to normal functioning. 

  • Miter Saw Armature

An armature plays a critical role in the running, and the spinning of the blades of your miter saw. It helps in the normal functioning of the motor. When your miter saw starts producing the grinding noise, you should open your miter saw and examine if the armature is in good shape. If you are a novice, you could use the help of an expert to solve this issue. Replacing the armature will get your power tool back in shape.

Although it is normal for the miter saw to produce noise while undertaking the various woodwork duties, grinding noise is a clear indication that some part of your miter saw has malfunctioned. You should examine the bearings, the brushes, and the armature to determine if they are in good shape. If any of the parts have spoilt, it is recommended that you immediately replace them.