How to Fix Orbital Sander Spinning Too Fast Problem

Sanding wood using an orbital sander is a very delicate job. You have to be careful about the speed of the sander. If the speed is too fast or too slow, in both cases the surface of the work-piece won’t get a proper finishing.

Today in this article, I am going to talk about an orbital sander spinning too fast, why it happens and how you can fix it. But before that, I will talk about the spinning speed of both an orbital sander and a random orbital sander.

Does an Orbital Sander Spin or Move in Orbit?

Before I talk about why an orbital sander spins too fast, here are a few things that I must clarify.

You should know that an orbital sander has a pad that moves by following an orbit. It doesn’t actually spin. The orbit is usually just a small circle. The pad only follows this small circle. Usually, the pad of an orbital sander is square or rectangular in shape.

On the other hand, a dual-action orbital sander or a random orbital sander contains a round pad or disc. This round pad, just like above, circles an orbit but at the same time, it rotates as well.

So, when one asks how fast does an orbital sander spin, it means how fast it is circling the circle. And the answer is simple. It depends on how deep polishing or sanding you are doing.

There is a speed controller to control this speed. If you are doing a lighter layer of sanding, then the speed should be low. But for a deeper layer, the speed should be relatively faster.

Speed of a Random Orbital Sander

When one says how fast should a random orbital sander spin what he wants to know is how fast its pad or disc is spinning.

The disc of a random orbital sander should not spin much. If you position the disc parallel to the work-piece, the rate of spin should be the least. As you keep changing the position the speed should be increased by the controller.

There are a lower limit and an upper limit of speed marked on the controller. Based on the positioning I gave above; you have to adjust the speed with the controller.

Reasons – How to Find Out the Problem:

Now it’s time for you to learn the reasons behind an orbital sander spinning too fast.

#1. A problem in the Bearing (for Both Electric & Pneumatic sander)

When you use an orbital sander for a long time, the bearing of the sander (where disc mounts) stiffs up.

This causes the disc to speed up and spin at a high rate. At this point, even after the tool is stopped the disc will rotate.

#2. Potentiometer Has a Problem (for Electric sander)

The speed of an orbital sander is controlled by a controller. The controller controls the speed through a potentiometer and a transistor. If you look inside, you will find a potentiometer and a transistor inside the orbital sander.

The potentiometer measures the voltage and sends a signal to the controller.  According to this signal, the voltage is controlled. When the potentiometer stops working, the voltage cannot be controlled. So in this case, as voltage rises, the speed will rise with it.

#3. The Transistor has Issues (for Electric sander)

Voltage control also depends on the transistor as I have said. A transistor takes a voltage and either rises or drops it. Both step-up (rises the voltage) and step down (drops the voltage) transistors are used here.

However, if the transistor stops working, then the input voltage cannot be dropped according to your needs. In such cases, the high voltage will surely cause the sander to spin faster than usual.

#4. The Speed Control Regulator (for Air/Pneumatic sander)

An orbital sander will spin too fast if the regulator stops working. The regulator of the speed controller is connected to the transistor and the potentiometer using a few wires.

If one of these wires get cut when the regulator is on full speed, then you won’t be able to control the speed with the regulator. And so the orbital sander will unnecessarily spin fast.

How to Stop Orbital Sander from Spinning Too Fast:

Primarily you can pull apart the orbital sander and check the speed controller. Also, check the bearing to find out where the problem started in the first place. Then you can follow my given procedure to solve the problem.

#1. Solving the Bearing Issues (for Both Electric & Pneumatic sander)

If you find that the bearing is stiffed and that’s what causing the sander to spin faster, then there is only one thing you can do. That is, you have to replace the bearing. The bearing of a sander will eventually stiff up.

But it depends on the quality that how fast will this happen. A high-quality bearing can go on for years, whereas a low-quality bearing will stiff up within a few months. So always try to have a good quality bearing.

#2. Replacing the Potentiometer (for Electric sander)

If you check inside and find out the potentiometer is dead, then it is time for you to change the potentiometer. If you don’t change it, the sander will always take all the input voltage and hence spin really fast.

Such a situation is not good for your orbital sander. Because frequent input of such high voltage will eventually lead to machine failure. So, you have to replace the faulty potentiometer as soon as possible.

#3. Getting a New Transistor (for Electric sander)

The risk with a faulty transistor is similar to the risk with a faulty potentiometer. So, after checking the inside of your orbital sander, if you find a faulty transistor you have to replace it with a new one.

You can find a new transistor for a sander at your nearby hardware store or online as well. Make sure it is similar to the old one you had. By similarity, of course, I mean the similarity in voltage rise or drop level and not in quality. You should always get better quality if possible.

#4. Fixing the Regulator (for Air/Pneumatic sander)

If you find any wire torn in the regulator, you don’t have to replace it by getting a new one. You can simply reattach the wire and you are good to go. But while reattaching, make sure you have disconnected all the power supply.

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

We solved the common problems of the Air & Electric orbital sanders of the following brands.

• Dewalt
• Ryobi
• Ridgid
• milwaukee
• makita
• Festool
• Black & Decker
• Porter Cable
• Craftsman
• Skil
• iBell

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

Conclusion

From now on, I hope you will not have any problem with your orbital sander spinning too fast. You should know that though there are different brands for orbital sander in the market, their functions are all quite similar when it comes to spin speed. If you own either Ryobi, Dewalt, Ridgid, Milwaukee, Makita or any other electric da sander you can follow the above procedure to solve the problem easily.

Last Updated on July 11, 2020 by Rogers Weber

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