Random Orbital Sander - Should the pad be visibly spinning?

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Forum topic by steambc500 posted 08-17-2021 11:20 AM 688 views 0 times favorited 6 replies Add to Favorites Watch
View steambc500's profile


6 posts in 275 days

08-17-2021 11:20 AM

Topic tags/keywords: random orbital sander sanding power sander question

Hey Guys,

I noticed with my Dewalt ROS, it took very little downward pressure to cause the pad to stop visibly spinning. Later, when the speed control pot failed, I bought a Ryobi ROS since I’m invested in the batteries. Again, with this sander, it takes barely any downward pressure at all to stop the pad from spinning.

My question is, is the pad supposed to be visibly spinning around for the unit to work, or is the sanding pad still doing its work while the pad appears to be stalled or standing still? Logically it seems that the pad should be spinning, but the reason I question this is that both of my sanders require hardly any pressure at all to stall the spinning.


-- Brian from Connecticut. Unbiased Tool Reviews at

6 replies so far

View syenefarmer's profile


594 posts in 4533 days

#1 posted 08-17-2021 03:48 PM

Try using the sander without any downward pressure at all. While most of us are guilty of applying at least some downward pressure technically the ROS should do its job without any downward pressure.

View splintergroup's profile


6918 posts in 2675 days

#2 posted 08-17-2021 05:18 PM

There should be some rotation and always should be oscillation.

The oscillation is from a counter weight, but the rotation is from a belt under the pad. This belt is designed to slip (and reduce rotation) if too much downward pressure is used.

With my PC VS333 (5” ROS) that belt just wore out. I replaced it with a standard “O” ring from the hardware store and it has been working like a champ.

View steambc500's profile


6 posts in 275 days

#3 posted 08-17-2021 05:21 PM

Thanks guys. It seems that my Ryobi slips way too easily, just as my dewalt did.

When I let up too much on the pressure, the pad will tend to chatter. It’s as if there’s not sweet spot. Either chatter or stall.

Being very unafraid to take things apart and modify, I’m going to see if I can take down the Ryobi and perhaps replace the belt with a very slightly smaller one if I find one in there.

Thanks again!

-- Brian from Connecticut. Unbiased Tool Reviews at

View pottz's profile


25663 posts in 2437 days

#4 posted 08-17-2021 06:04 PM

yeah id say if the disc isn’t spinning it’s not dont need much pressure but just let your hand rest on top,that will give all you need.

-- working with my hands is a joy,it gives me a sense of fulfillment,somthing so many seek and so few find.-SAM MALOOF.

View steambc500's profile


6 posts in 275 days

#5 posted 01-24-2022 08:01 PM

I’ll experiment some more and see how it goes. Methinks this is more a case of “operator error” than anything else.

-- Brian from Connecticut. Unbiased Tool Reviews at

View jonah's profile


2283 posts in 4752 days

#6 posted 01-24-2022 08:44 PM

You really never want to be pressing downward much harder than the weight of the sander. If the sander sitting on wood without you pressing down is not rotating or oscillating, then there’s absolutely something wrong with the sander.

In my experience, 95% of people press down too hard on their ROS.

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