How to Fix Orbital Sander Slows Down Problem

As an orbital sander user, you often have to deal with a very common problem of a sander. That is, it slows down after a while.

However, if you are already facing this problem and looking for a solution, then this is the right place for you. I have faced this problem several times and each time it happened for a different reason.

So, today I am going to share everything that you need to know about why orbital sander slows down. But before that, I would like to add a little something about the types of orbital sander so that you can catch the gist quickly.

orbital sander slows down

Orbital sanders are of mainly two types. Electric-Powered orbital sander which runs on electricity. The other one is Pneumatic orbital sander which is run by airflow or air power [Air Sander].

So now I will show you the reasons why an orbital sander slows down.

Why An Orbital Sander Slows Down?

There are many reasons for an orbital sander to get slower with time. Electric and pneumatic sanders have different reasons behind this. But they also share some common reasons as well.

I have talked about them separately as some of you own pneumatic while the rest of you own electric orbital sander.

1. For an Electric Orbital Sander:

1. Fix the Torn Cord

Electric orbital sanders have many cords and wires inside. First of all, there are cords which connects the motor to the power supply.

Tighten Loose Joint Any Point of cord

If there is any break in the wires or the cords, that will create a high resistance for the electricity to flow through. Note that I am talking about a break not torn. It means there is a high resistance created during a loose joint at any point in the cord.

Repair Orbital Sander Torn Cords

On the other hand, if the cords were torn, no current would flow at all and hence the sander won’t run. However, higher resistance will lower the current flow and thus the power will decrease as well. When the power decreases, the sander spinning very slowly.

2. Ensure A Good Power Source:

Another reason for power decrease is when the extension cord is too long. A longer cord creates more resistance which eventually leads to lower current flow hence lower power supply. A damaged cord or wire does the same.

Remove Lot of electric powered devices one power circuit

Sometimes when you connect a lot of electric powered devices and tools in one power circuit or extension, the extension gets overloaded. When it happens there occurs a shortage of amperage.

For this, the power divides down and hence your sander gets a very low amount of power. This is another possible reason for an electric orbital sander to slow down.

3. Check the Motor and Capacitor

Replace Electric Orbital Sander Motor
Finally, if the motor of the electric sander is damaged, (not only the wire winding but also the capacitor) then there will be low speed and so the orbital sander will rotate slowly.

2. For a Pneumatic Orbital Sander [Air Sander]:

1.Check Damaged Rotor and Blade

The main principle on which a pneumatic orbital sander runs is, air flows into the sander. Then it hits the blades which are attached to the rotor. The blades are made in such a way that when the air hits them, they move and the rotor rotates.

Replace Air Orbital Sander Rotor and blade

So, if the blades are damaged (if it has holes or cavity), instead of hitting the blades, some of the air will flow right through. This will make the sander to slow down.

2. Clean the Rusty shaft

Another possible reason for a pneumatic sander to slow down is a rusty shaft. When the shaft becomes rusty, its surface becomes rough that makes the turning of the shaft slower.

3. Common Reasons (for Both Electric & Pneumatic):

1. Clean Dust and Rust

For both electrical and pneumatic orbital sander, the brushes are common. If there are dust and rust clogged in the brushes, then the sander will slow down due to clogging.

You can find a speed controller in your sander (whether it’s electric or pneumatic). The job of this controller is to increase the power when the load or the pressure increases. When this speed controller fails, the speed of your sander will get slower as you apply more pressure on it.

2. Check the Bearing Spin Freely

One of the main parts of an orbital sander is the bearing. If they cannot spin freely the sander will spins slow motion. Sometimes the bearings contain dirt that makes them hard to spin.

3. Disassemble Carefully

And finally, if you disassemble your orbital sander for cleaning and then reassemble, then something (like the bearing or the rotor or the shaft) can get knocked out of alignment. When this happens, the sander will get slower.

How to Prevent Random Orbital Sander from Slowing Down?

Now that you are familiar with the reasons for a sander get slow, it will easier for you to prevent your sander from getting slower, or fix it if it is already there.

For Fixing an electric orbital sander:

First of all, if you own an electric orbital sander, here are the things you should follow.

1. How to Fix the Torn Power Cord:

  1. Check the power cord to see if you can find any breaks there. You can use a multi-meter to calculate the resistance of the cord. If there is a high resistance between two points, then the break is between those points. If you find such breaks, tighten the loose joint or simply change the cord with a new one.
  2. Try to use a smaller cord instead of a long one. The longer the cord the more resistance it will have. For this, the power supply can get lower.

2.Fix the Low Power Source

  • If you have a lot of electric devices connected to the same circuit, disconnecting the other ones will give enough power to your sander to spin faster.

3. fix the Motor

  • You can check the motor of your electric orbital sander to see if there are wire burnings, or not. If so, then you have to change the motor of the sander.

For Fixing an Pneumatic orbital sander:

So, these are the things that you can do for an electric orbital sander. Now comes the pneumatic orbital sander.

1. make the shaft smoother

  1. You have to keep the sander away from water or moisture so that the blades and the shaft don’t get rust on them. Rust is one of the main reasons for a pneumatic sander to slow down.
  2. If you find dust inside the shaft and the blades, clean these thoroughly and apply some lubricator to make the shaft smoother.

2. Fix Holes or Cavity

Sometimes, too much dust and rust can create holes or cavity on both the blades and the rotor. If you find holes, you must replace the rotor and the blades, so that air can hit the blades properly.

For Fixing both Pneumatic and Electric sander:

Now let me show you what common things you should follow (for both pneumatic and electric sander) to prevent your orbital sander from getting slower.

1. Check, Clean or Replace Brushes

At first, you have to check the brushes (after disassembling) to see if they are dusty or not. If you find dust there, clean them properly. Sometimes the dust sticks hard on them and it becomes really hard to clean. In such cases, it is easier to replace the brushes with new ones.

2. use lubricants to clean the bearings

You can disassemble the sander and check the bearings. For moisture the bearings get rusty. So, you can use lubricants to clean the bearings. If it doesn’t take off the rust, replace the bearings with new ones.

3. Fix the Speed Controller

If you see the speed controller of your orbital sander is failing, then you have to replace the speed You can use the manufacturer warranty to replace the controller if you still have warranty time left. Otherwise, you can do it yourself from any power tool shop.

4. Reassemble the parts carefully

Finally, after disassembling, very carefully reassemble the parts so that they are perfectly aligned. Otherwise, even after cleaning you will still get a slower spin speed from the sander.

clean sander dust


For my final words, I would like to say that, you should clean the inside of your electric sander every week. Even if you don’t use it regularly, you should clean it. Otherwise, dust gathers and hence the sander spinning slowly. Also, keep in mind that moisture is the main reason for rust. So, keep your sander safe from a humid condition and also away from water.

There are many brands of the electric da sander in the market and their functionalities almost same. For instance:

  • Ryobi
  • Dewalt
  • Milwaukee
  • Makita
  • Festool
  • Black & Decker
  • Porter-Cable
  • SKIL
  • iBELL

If you use other brands and face the same problem then you should try the above methods to fix air or Orbital Sander Slows Down problem. So, you can repair any types of brands.

Last Updated on July 11, 2020 by Rogers Weber

[As an Amazon Associate I earn from qualifying purchases.]


Add a Comment

Your email address will not be published. Required fields are marked *