Random orbital sander variable speed

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Forum topic by dansnow posted 04-13-2018 12:05 AM 1393 views 1 time favorited 8 replies Add to Favorites Watch
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330 posts in 2724 days

04-13-2018 12:05 AM

I wasn’t sure if this question should be in finishing or power tools. I recently got my first random orbital sander and the darn thing is driving me nuts!! I cannot keep it from jumping and hopping around when I try to use it It’s almost like the sanding pad is rubber and grabbing the surface. If I turn the speed all they way up it’s smoother, but unlike my pad sander it has a mind of it’s own. I’m about ready to chalk it up as a bad investment. I only bought it because my 30 year old pad sander is wearing out and I had read that random orbitals gave a superior finish.

So, help, what am I doing wrong with this darn thing?

-- Snow's Wooden Toys & Gifts

8 replies so far

View Loren's profile


10689 posts in 4528 days

#1 posted 04-13-2018 12:13 AM

Is it brand new? refurbished?

They are a little hard to hold onto when working
properly, but hardly so hard to control as you’ve
described. They do have parts that can wear
unevenly and cause misbehavior though.

You’re supposed to bring them up to speed before
putting them to wood. Not doing that may cause

View dansnow's profile


330 posts in 2724 days

#2 posted 04-13-2018 12:54 AM

It’s brand new, a TackLife. I tried the letting it get up to speed and that did help. It has a hard plastic dust collector, and I have found that if I put one hand on it and the other on the palm grip on top it is a lot easier to control, but having to use both hands is a bit of a pain as I don’t always have the opportunity to use clamps.

Thanks for the tip, it helps.

-- Snow's Wooden Toys & Gifts

View crowie's profile


3961 posts in 2831 days

#3 posted 04-13-2018 03:50 AM

G’Day Dan,
Not a brand we have downunder.
I use a Bosch Blue unit which I find very good.
I found this video on youtube and this blokes gives yours a good rap!

-- Lifes good, Enjoy each new day...... Cheers from "On Top DownUnder" Crowie

View Rich's profile


5966 posts in 1469 days

#4 posted 04-13-2018 04:17 AM

My old Porter Cable sander did that. It was from the early ‘80s, and was a bear to handle. I still have a couple of projects from those days with “donuts” in the finish. No one would notice them unless I pointed them out, but they’re there.

Contrary to what might be intuitive, starting the sander on the surface of the wood helps prevent that swirly dance some of them do. Set it flat on the board, cup it in both hands down near the base and switch it on. You should be able to practice that and get good results. There’s something about certain sanders that makes them want to swirl around when they touch down. I have no idea why. Some gyroscopic effect maybe.

That said, in the 5-inch ROS family, I have Makita, DeWalt, Bosch and Porter Cable (not the original one mentioned above) and none of them exhibit that problem. The PC is probably the worst sander of the bunch, and the Bosch the best, but they are all useable.

-- Half of what we read or hear about finishing is right. We just don’t know which half! — Bob Flexner

View dansnow's profile


330 posts in 2724 days

#5 posted 04-13-2018 11:31 AM

Thanks for the info and the link to the review. The fellow in the video sure made it look easy, I didn’t see either one jump once. It looks like I just need to use the thing and get used to it.

-- Snow's Wooden Toys & Gifts

View EarlS's profile


4003 posts in 3228 days

#6 posted 04-13-2018 11:50 AM

I have a Mirka Deros which has a variable speed function. At low speeds it wants to jump a bit on wood that isn’t especially flat or when I try to move too fast with a coarse disk. It will also jump if I push down on the sander rather than let it sit on the wood. I typically hold it at the lowest part of the motor housing, just above the ROS section. Generally, I only use the lower speeds with the really fine discs (320+). Let the ROS do the work, don’t force it.

-- Earl "I'm a pessamist - generally that increases the chance that things will turn out better than expected"

View ralbuck's profile


6596 posts in 3146 days

#7 posted 04-13-2018 08:18 PM

I have a Bosch with no issues; unless I press hard with a very rough paper on it. Otherwise it glides nicely with one hand. I also have a DeWalt—not quite as smooth; but, still very manageable with one hand.
I am also a small not overly strong guy.

-- Wood rescue is good for the environment and me! just rjR

View cabmaker's profile


1745 posts in 3689 days

#8 posted 04-13-2018 08:25 PM

sounds like you need to replace the pad with a soft one

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