ROS jitters and jukes!

[sachbvn]

So.... what exactly causes a ROS to jerk and pull real hard when sanding sometimes?

Is it just not liking the grain it's on at the time? I'm only talking about 120 or 220 grit paper.

Sometimes I'll be sanding a board.......everything's fine..... JERK, JITTER, JUKE.....the sander is all over the place. Like a cat with it's tail on fire! Then later on it works just fine. WTH?


Zac

[TDHofstetter]

Juke. THERE's a word I don't think I've ever heard before unless it was followed very closely by "-box".

If it tips a long way up on edge, it'll beat yer arm to death till it gets settled back down flat, but I've got a feeling you're talking about it doing that when it's already flat.

Without actually spending the time to analyze it, I'm gonna' guess that it gets a little wad of wood flour packed under one side of the pad but not all the way around. That little wad will have very different friction characteristics from those of the sandpaper, so it'll "get funny" until the wood flour is cleared back out again.

That or... possibly... the RO bearing isn't quite up to par any more and finds a spot where it doesn't want to rotate - just hangs there. That'll make the pad act freaky, too.

[Ruffnek]

Feb 10, 2010 19:12:37 GMT -6 TDHofstetter said:

Juke. THERE's a word I don't think I've ever heard before unless it was followed very closely by "-box".

Tim, it's obvious you aren't a sports fan. ;D

Zac, is your sander a 5" or a 6" ROS? Some of the 6" sanders are very aggressive, especially the dual mode sanders and can be difficult to control.

If it's a 5" and occassionally goes crazy, then I think there's likely something wrong with the sander, like Tim said. Does any strange or different sound accompany the erratic motion?

[sachbvn]

Thanks guys - kinda furthers my thought that my ROS might be running low on life.

Tim, this is happening completely flat, on a nice wide board.

Cody - it's a 5" ROS.

Ok - ready for this guys? You won't believe what brand it is....drum roll...... CRAFTSMAN Professional!!! Actually - it has been fine (my first ROS so I have NOTHING to compare it to.)

I have been thinking for a little while that the bearings might be going to pot - it was make a little bit of a funny noise when it winds down... has been for a little while. I am assuming I will at some point in the not to distant future have something lock up and seize on me.... I should pry think about replacing it before that happens being it's my only ROS.

The PC ROS sanders get good reviews?

Zac

[Ruffnek]

My favorite ROS was a 5" Bleak & Darker until the bearings failed on it.

I searched the Fine woodworking archives and the last 5" ROS review I found was from 2006. Bosch was awarded Best Overall and Best Value, too.

Wood Magazine had a review from 2008 and the PC 390k got Best overall.

Porter-Cable also has the new low profile ROS only it's about 2 x the price of the old model.

I use a DeWalt that I got out of the bargain bin at HD...it was missing the dust bag which I don't use anyway. I use a vacuum.

[art3427]

It's the orbital bearing. I've replaced hundreds of them over the years. It's been a while since I bought one but they should be in the $5.00 price range.

art

[dburkhart]

Your bearing is going bad i have the exact sander and had to change the bearing after i did a diningroom table. The bearing is easy to change. i took it to work and pulled it off with a set of small gear pullers.Yuu could do the the same with a hammer and a punch

[sachbvn]

What I might do is secure a new sander - THEN look into getting a new bearing and trying to replace it. That way I have a back-up anyways, but would also get experience changing out a bearing. Yall can expect to be helping me!


Zac

[dcarter636]

"What I might do is secure a new sander - THEN look into getting a new bearing and trying to replace it. That way I have a back-up anyways..."

Zach that was expressed like a man with many years of tool rationalization and negotiation experience.

[Mark T]

You definitely need a new sander... or two. I keep different grits on different machines for easy changing. Reach down and get the 80. Finish, put it back, grab the 150. And so on.

The bearing is easy to tackle. Don't tell her that until you have a new RAS in hand, then walk in one night and say "You know honey, I MIGHT be able to rescue the old sander". She'll think you are brilliant, and you get a new toy.

This DOES work.

On edit- If nothing else, Sears has a great website that will break the parts down and show the assembly. Owner's manuals are there too. Y'all can bash Sears all you want, but there are some good things about their stuff... however, that is another entire thread.

[sachbvn]

Mark,

That is where I was going to find out which part I exactly needed.... I will be getting a new sander - it's a certain, just not sure when I'm going to order it.


Zac