Belt Sander Stopped Spinning – Common Reasons and Solutions

For countless DIY and professional projects, belt sanders are irreplaceable tools. One can’t possibly have a smoother finish without using a sander and belt sanders make your job faster, quicker, and more precise.

But nothing would be possible if your belt sander stopped spinning or not working properly. Throughout the article, we’ll try to mention some common issues. Also, we’ll solve them in some easy-to-follow step by step instructions.

belt sander stopped spinning

Why is Belt Sander Stopped Spinning or Not Working Properly?

There are several reasons to stop belt sander spinning. Electric and Air/ Pneumatic sanders have different reasons behind this. But they also share some common reasons as well. I have discussed details through my article. So, stick with me till the end.

1. Air Valve Problem (For air Belt Sander)

Like all other pneumatic tools, the air belt sander can also be subject to an air valve issue. If anyhow the air valve gets obstructed or stays closed, your tool won’t get the power to start.

Air Belt Sander Air Valve problem

How to Fix Air Valve Problem

  • First of all, check if something is in the way of air tunnel that’s stopping the valve from opening or closing. Then, remove it and see if it solves the issue.
  • After that, check if the valve is functional or not. A faulty valve can also be responsible for this issue. Replace it, and you’ll be good to go. Overall, you should make sure that the tool is getting enough air pressure.

2. Throttle Lever Problem(For air Belt Sander)

The throttle lever is responsible for channeling the air power to spin the belt. If your throttle lever can’t move freely, you might find that the belt is not rotating.

Pneumatic Sander Throttle Lever Assembly

How to Fix Throttle Lever Problem

  • Clean the throttle lever mechanism properly and make sure that the thing is moving freely. If the problem still exists, replace the throttle lever mechanism, and you’ll have it fixed.

3. Loose Head Problem(For Pneumatic Belt Sander)

This is not a common problem, but you could check this when your air belt sander stopped working. So, if your sander starts sanding again by only tightening the screws, a lot of your time will be saved. There might be a situation where the internal rotor is spinning, but the belt is not rotating.

how to Fix Air Sander Allen loose Screw

How to Fix Loose Head Problem

  • So, check the head that has a counterbalance on it and see if the screw is loose. That loose screws will make the belt not rotating. It might be an Allen screw. So, tighten it and start the sander again. This will solve the issue.

4. Drive Belt Problem (For Electric Power Belt Sander)

One main reason for the belt sander to stop spinning could be the drive belt problem. Make sure that your tool doesn’t have a power problem. You can check it by plugging in the power cord and feel if it’s vibrating or not.

Electric Belt Sander Drive Belt problem

If it’s vibrating, it’ll mean that the tool got power, and the motors are working fine, but still, the belt sander stopped spinning. This could indicate that your drive belt is not working. So, you’ll have to open the belt cover to replace the damaged drive belt.

How to Fix Drive Belt Problem

  1. Firstly, unscrew and remove the side belt cover from the side of the belt sander.
  2. Secondly, you’ll need to remove the belt by removing the lower pulley. For some models, you’ll not need to replace the lower pulley. Whatever it is, take the right action and remove the drive belt.
  3. After that, see the belt number on the belt and replace it with the exact belt. You’ll need to use a little bit of force to place the belt in place.
  4. Now, put the lower pulley back to its position and tighten the screws.
  5. Finally, reinstall the side belt cover and start the tool. I hope this helps solve your problem.

5. Power Problem (For Electric Sander)

Another common problem of belt sander not working is caused by the power problem. You woke up one beautiful morning, plugged in the tool’s power cord, and hit the button. But to your surprise, the tool seems dead. There can be many reasons that your belt sander is not rotating. Let’s see some possible power issues.

  • The power cord might be problematic.
  • The switch could be problematic.
  • The inner-wiring could be faulty.

How to Fix Power Problem

Let’s follow step by step instructions to check all four issues and act accordingly.

replace power switch

  1. In the beginning, open the belt sander after detaching it from the power socket and grab a voltage-meter to check the voltage across the power cord.
  2. Then, put two probes of the meter at one side of the power switch where the power cord meets the switch. If you don’t see zero voltage, that’ll mean the power cord is working fine. Otherwise, change the power cord.
  3. After that, put the probes on the other side of the switch. If you see zero voltage across the switch, it’ll mean that the switch is faulty, and your problem will be solved just by replacing it.
  4. Finally, check the internal wiring with the same process. See if you get zero voltage at any point and act accordingly.

6. Motor Carbon Brushes Problem (For Electric grinder only)

Carbon brushes are essential for electric motors. It ensures good conductivity and powerful rotation of your motor. With a faulty carbon brush, your motor will get damaged in the long run. In the beginning, problems aren’t noticeable, but the situation gets worse over time. The worst-case scenario is that your belt sander stopped working. So, you’ll need to replace the carbon brushes in the right time. Let’s see how you can replace them.

belt sander stopped working Carbon Brushes problem

How to Fix Motor Carbon Brushes Problem

  1. Firstly, look for your motor’s orientation and locate the position of the two carbon brushes.
  2. Secondly, use a screwdriver to open the hole and take out those motor brushes.
  3. Thirdly, put two new carbon brushes in the holes and make sure that you reinstall them correctly. Loose contact or faulty installation will not solve this issue.
  4. Finally, close the holes and start your belt sander. That should do it.

7. Motor Armature Problem (For Electric powered)

This armature is the heart of a motor. For the damaged armature, you’ll see that your belt sander is not rotating. But can we solve armature problems by ourselves? The answer depends on your expertise. If you don’t have any knowledge about the electric motor, you should take it to your local technician.

Electric Belt Sander Motor Armature not working fix

How to Fix Motor Armature Problem

In this part, we’ll learn to detect if our armature is faulty or not. We’ll do three tests, and if the armature fails any one of the tests with the commutator, we’ll consider it faulty. Let’s see how to do those three tests and interpret the results. To do this, we’ll need to open the belt sander, take out the motor completely, and get a meter with the lowest resistance settings.

  1. The first test includes touching the probes of the meter on two bars of the commutator 180-degree opposite of each other. You’ll see that there are many bars and you have to check all of them. The value of the resistance isn’t our main concern here, but the consistency is. If you see any drop or spike of resistance between any two bars, it’ll mean that there is a short connection for the drop and broken connection for the spike in resistance.
  2. The second test includes touching the probes on two adjacent bars of the commutator. Do the process similar to the previous one and look for the defined signs. The interpretation is also the same for this test.
  3. The third and final test is watching the resistance between a commutator bar and an armature stack. Touch the probes on a commutator bar and an armature stack and see if it shows one or an open loop. It means that there should be no connection between them. Check all bars and stacks. A faulty armature will show some value in this test.

8. Dirt or Gum Deposit Problem (For Both Air & Electric Belt Sander)

This is a common problem for both air and electric belt sander to stop rotating. After many hours of using the tool, the dirt gets deposited inside the tool. As there are friction and heat involved in the sanding process, it’s very likely to have solid deposits inside. As a result, you saw that the belt sander stopped spinning.

How to Fix Dirt or Gum Deposit Problem

  1. To solve this issue, you simply need to flush the sander using a gum solvent.
  2. If you see that the problem still exists, you should breakdown the tool and clean it thoroughly.
  3. Finally, lubricate different parts and reassemble the tool.

9. Worn Parts Problem (For Both Electric & Air Belt portable Sander)

Another common problem for every single tool known to human civilization is the worn part problem. This issue can be so severe that your sander won’t spin because of it.

Among the worn parts, the most common ones are bearings and pulleys. Because of the bearing issue, you’ll not get enough speed. On the other hand, for pulley issues, you might see that the belt is skipping or not spinning at all.

How to Fix Worn Parts Problem

  • There’s nothing much to tell here. This requires only your diagnosis and finding out the worn parts. Then, shop the matching parts and replace them.

What happens if you use different types of brands and face the same problem?

In the last part, we’ve solved the common problems for both air and electric belt sanders. Those problems can occur in any of the following brands.

  • Craftsman
  • Ryobi
  • Ridgid
  • Skil
  • Wen
  • Bosch
  • Astro
  • JET
  • Grizzly

So, if you face any of the problems mentioned above for those brands’ sanding tools, you can solve them with our guide.

Final Verdict

“Belt sander stopped spinning in the middle of the job, and I don’t know what to do.” That’s one of the most common dialogues we heard from many professionals. After reading this article, you’ll at least keep your cool and diagnose where the problem might be. After that, you can take action according to our instruction or take it to a technician if the solution seems more complicated. We hope that you won’t have to waste time like before anymore.

Last Updated on June 2, 2020 by Rogers Weber

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