Rotex 125 problem in RO mode

[Zaphod]

Greetings,

Bought a Rotex 125 recently with the thought of replacing my PC belt sander and 333vs RO sander.  In rotary mode, it works like a charm and is a viable belt sander replacement.  Agressive and controllable at all speeds, pressure, and vacuum level.  The belt sander has found a new home via craigslist.

In RO mode, the sander is difficult to control and chatters badly. 

• I've noticed little difference in the chattering with different grits (36-180). 
• Lowering vacuum strength helps a bit, but the problem persists.
• If I'm really careful adjusting the sanding pressure, the chattering is minimized but still present. Generally, zero downward pressure (even a very slight lifting) seems to work best.
• Lowering the speed to anything below maximum makes the chattering progressively worse.

For comparison, I broke out my 333vs and it's smooth as silk at any speed, vacuum, or pressure.
I've never heard of this complaint with the RO mode of the Rotex.  Guess I'll have to hang on to the 333vs for a while.
Perhaps I'll see if the local Woodcraft has a Rotex 125 there I could compare with.

Any one else experience this problem?

- As an aside, the RO125 came with a nice assortment of sanding discs, not the single disc mentioned elsewhere (including Festool's web site).  A reasonable inclusion for a $360 sander!

 

[eweber]

Hi,

I had the exact same experience.
It took me a little training before I could use the RO 125 in RO mode without chatter.

I usually use it at full speed with the dust collection set a little over half power on my CT22. I do use only very little pressure.

I am not sure what I was doing wrong, I have a feeling that I was not holding the sander completely flat.

(I also got the assortment of abrasvies)

 

[Zaphod]

Other than sander speed, pressure, and vacuum force I'm not sure what variables are left for manipulation with regards to an operator technique that eliminates the chatter in RO mode.  As you suggested, I've tinkered with "leveling" the pad to the surface with minimal effect.  I find it hard not to have the pad fairly flat with the sanding surface without conscious effort.  Seriously; operating a RO sander is probably the least skill sensitive power tool in the shop.  Frankly, I'd be amazed (and thrilled) if a change in technique could possibly have a significant effect in the sander's operation.  That said, I'm all ears as far as suggestions to eliminate the chatter problem. 

 

[larrysee]

I understand your frustration. When mine was new, I had the same problem. I griped to Uncle Bob and got suggestions as already mentioned, but was in the middle of a project, so kept at it. By the time I finished, the problem had gone. I cannot explain it, but getting the feel of it and breaking in come to mind.

Regards, Larry

 

[Jeff W.]

My RO 125 never stopped chattering and hopping.  It did this in both sanding modes.  It was really bad in rotex mode, and quite bad in ro mode.
I complained to the place I had purchased the sander and they told me that there could be nothing wrong with the sander, but I must change the way I sand with it.  I tried that for a few months and then decided it was the sander and not me.  I sold the the RO 125 and got an ETS 150/3 which is a great sander.  I'm a member on woodweb, and a member there was told that the RO 125 is not intended for wood cabinet and furniture sanding...    I know many members on woodweb who have had problems with the RO 125.  The other problem I had with the RO 125 is that it sanded so slowly in random orbit mode.... 

 

[Zaphod]

Went to my local Woodcraft and tried their RO 125 FEQ and it was much smoother than mine.  Called Festool and they agreed that my sander was not performing as expected and sent me a new sander promptly without any hassle; they thought the counterbalancer may have been misaligned.  The new sander arrived in two days and is much easier to control in RO mode.  It's still nowhere near as smooth as my pc333; perhaps a consequence of the right angle design? 

I bought the sander in large part because of its promise of dual functionality.  Based on the three RO 125 FEQ's I've used:  In orbital mode it's outstanding, in random orbit mode it requires a lot more effort to control than my conventional RO sander.  Anything less than full speed results in excessive vibration and chattering.  All in all, a nice sander, but not the sanding panacea it's purported to be.  I've never used another right-angle RO sander, perhaps they're more difficult to control than the Festool.  In random orbit mode, my $75 pc333 is preferable to the RO 125 due to it's controllability and lack of vibration.

 

[denverdad]

Zaphod, I had similar problems with an ETS 150/3. See my thread here:http://festoolownersgroup.com/index.php?topic=1208. I exchanged it, and the new one does not seem to have the problem.

-Randy
ps. huge fan of your name

 

[hammer6048]

Having the same problem with the chatter, after reading all the posts it appears that there is no solution, am I interpreting this correctly?  Would like to get this solved as opposed to purchasing a different sander.  Thanks.

Mike

 

[semenza]

Having the same problem with the chatter, after reading all the posts it appears that there is no solution, am I interpreting this correctly?  Would like to get this solved as opposed to purchasing a different sander.  Thanks.

Mike

Hi Mike,

  Welcome to the forum, or should I say happy first post !  [smile]

  How old is your sander?  Since no techniques , etc have solved the problem have you called Festool service?

Seth

 

[tbellemare]

Have you tried holding it by the tail?

I hold a Rotex in random orbital mode with one hand where the hose and cord connect. All I'm doing is taking the weight of the cord and hose off so it can float. You should not exert ANY pressure on it.

Tom

 

[Jeremiah9675]

I have a Festool ro125 that I bought during the recon sale that works flawlessly regardless of my technique . I have heard of this phenomenon before. I know a lot of guys on the FOG that swear by the Rotex break in period. Eric (bigerock) did a YouTube video on it. Before sending it out you should try this, it can't hurt.

 

[shed9]

Be aware that there is no science to the Rotex 'break in period' at all. There is no real valid technical reason why the machine would operate differently after being left to dangle running for several hours. It could be argued that the brushes will wear in slightly but this is fairly moot in this instance.

The break in period is relevant to the user and machine, not the machine left to run on a rope with no mechanical resistance.

That said, many people do it and swear by it and it is unlikely to harm the machine. If you feel it works for you, go for it.

 

[Skillman]

My next purchase is going to be a sander . But to read this thread that rotex 125 needs some kind of break in time is crazy . Leave it on for 8 hours is nuts . Was it just a bad unit . Why is it that a festool rep not come on and put it to rest what goes on with the Rotexs .

 

[tjbnwi]

I used all of my Festool (the only sanders I don't own are the 150 line) sanders right out of the Systainer. If there was a break in period it was concurrent with the work I needed to get done being done.

I find that of the sander chatters it's an indication the work piece is bouncing. I secure the work piece and the problem goes away.

Tom

 

[Scott B.]

It's a psychological thing.

 

[duburban]

I notice this the most when the material has bumps in it, high spots, low spots etc.

 

[Stephen B]

It's a psychological thing.

[size=14pt]
Reminded of the psychology this morning (AEST) when sanding back the ripsaw marks on 150/25mm rough sawn treated pine with RO 150 in ROTEX mode and 60 grit Granat.

Since new I have held it in much the same way outlined by Tom's response below/above. Sometimes I wrap my forefinger around the link from the dust exhaust to barrel casing.

I did not run mine in, (waste of electricity!) but soon realised that this was a powerful sander, lacking some of the finesse exhibited by my ETS150/3 and ETS125. Hold it tightly or with no balance and it would bite. Firm (in your mind) but gentle guidance with your hands and arms and you will be rewarded. Just a bit like the psychology of dog training.  [big grin] [eek]

[size=10pt]

[I know that some say the RO125 is more erratic than the 150 due to smaller surface area of pad.]

 

[hammer6048]

Well, thanks for all the feedback.  Have tried various techniques etc., the only thing I have not done is the "break in" as suggested, tomorrow I will call the Festool Service and see what they say.  Have eight other Festool tools this one is the most troublesome.  Thanks for the welcome and responses to my question.

Mike

 

[Rick Christopherson]

There is no break-in period required for the sanders. How do I know? Because it specifically says so right in the manual!!  [big grin] [big grin]

[attachimg=1]

Seriously though, I have examined the sanders in ways that regular users cannot afford to do. There is no need or benefit to performing a break-in. Some have said, "It can't hurt." Well it does hurt. It needlessly puts 8 hours of wear on a brand new tool for absolutely no purpose.