ETS 125 vibration

[kfitzsimons]

I have an ETS 125, probably 4 years old that is vibrating / jumping while sanding. I was sanding poplar doors with 150 grit paper and the sander bounces / vibrates / jumps, just a bit, but it's irritating. I purchased the sander from a guy on this forum, whom I would hope not sell me a bum sander. I've put up with this for about a year. Should I send it in for an inspection or should I just "eat" it and buy a new one?
    Kevin Fitzsimons

    kfitzsimons2003@yahoo.com

 

[Brice Burrell]

I have an ETS 125, probably 4 years old that is vibrating / jumping while sanding. I was sanding poplar doors with 150 grit paper and the sander bounces / vibrates / jumps, just a bit, but it's irritating. I purchased the sander from a guy on this forum, whom I would hope not sell me a bum sander. I've put up with this for about a year. Should I send it in for an inspection or should I just "eat" it and buy a new one?
    Kevin Fitzsimons

Kevin, since you've used it for a year I'll assume you figured out how to use it best for your needs.  That said I pretty much only use mine at full speed and that gives me the best results. 

My advice, give Festool's service department a call, they are in the best position to advise you.

 

[Administrator_JSVN]

Kevin,

Sorry to hear that you're having trouble with the sander. Make sure you're running it at full speed (setting 6). Running it at a slower speed can make it hard for the sander to overcome the friction caused by the abrasive. Also, if you're using it with a dust extractor, make sure you have the suction turn all the way down. Otherwise, the suction can actually pull the sander down into the material.

If both of those things are in check, I would recommend contacting the service department. If it's 4 years old, the sander will be out of warranty. But they can possibly help diagnose the problem and provide an estimate on any repairs that might need to be done.

Shane

 

[kfitzsimons]

Thanks guys. I was running it at about 3 on the speed dial and with the  vac turned all the way down. I'll try it at full speed.
Kevin

 

[Ken Nagrod]

Maybe the pad is damaged or worn?

 

[kfitzsimons]

I tried it at full speed and it seemed fine. I was just sanding a workbench top, not the nice poplar doors, but in the short time I messed with it, it didn't jump or vibrate. But what effect does sanding at full speed have on wood, compared to a slow or medium speed? My project was sanding the poplar doors after applying a sanding sealer / DA mix. Just a light sanding to take the raised fibers off to smooth them before staining.

 

[AlexThePalex]

But what effect does sanding at full speed have on wood, compared to a slow or medium speed?

kfitzsimmons, it's about overcomming the force of friction. When you run the sander at speed 1 and you press a bit the sander will come to a full stop because the force of the motor isn't strong enough to overcome the friction between the sandpaper and the wood.When you run the sander at full speed the power of the motor is large enough to make it slide over the wood without problem.

It's when you use settings in the middle when strange things happen because at one point the force of the motor is strong enough to overcome the force of friction and the pressure of your hand, and at another point it is not. Whenever the sander jumps it means that the friction was too high to overcome for a split-second, and in that split-second the pad of the sander comes to a full stop. But the next moment the friction is overcome, so the pad suddenly spins up again, and this force will cause the jump. Action = Reaction.

I never understood why they put speed dials in these small sanders. On a Rotex, yes I understand, you can actually see the difference because it has so much power and tuning it down to 1 won't make it uncontrollable or ineffective. But with these small 200 watt sanders it will. They got very little power as it is and running it at speeds other than full will only make working with it a pain. I never use them on a lower setting and I wish I had known this before I bought them because then I would have bought the versions without speed dial. In my humble opinion, speed dials on these small sanders only cause problems.

 

[mouppe]

Alex,

The speed dials can help if you need to lower the speed for polishing. They are not necessarily aimed at sanding tasks.

Richard.

 

[AlexThePalex]

Alex,

The speed dials can help if you need to lower the speed for polishing. They are not necessarily aimed at sanding tasks.

Richard.

All fine, but when do you polish with the RTS or the DTS? And an ETS isn't that good for polishing either. For polishing you want a rotary machine, not eccentric.

Btw, I'm not even sure if a low rpm is meant for polishing. The Rotex is good for polishing, but it's rpm only goes to 550, while the rpm of a real polisher like the Shinex goes over 2000.

 

[mouppe]

Alex,

You're right and I don't want to labour the point, but if you don't have a rotex or shinex then you'll have make do with using an RO sander for polishing, in which case you would want to dial down the speed.

In Festool's own polishing guide, they state the the ETS 150 or 125 can be used as an alternative to the Rotex on speed level 3-4 (though clearly it's not preferable).

I was simply answering the question "why put a speed dial in a sander?" Not wishing to go way off-topic.

 

[kfitzsimons]

thanks for the info fella's. The friction explanation is helpful. For polishing, I have a Porter Cable RO sander / polisher which is hard to beat. I've only used it on my car though. All seems fine with the ETS after your suggestions. Thanks.
  Kevin

 

[Administrator_JSVN]

Glad to see you got it sorted out, Kevin.  [thumbs up]

 

[kfitzsimons]

Valuable information. No fluff here! I appreciate the forum for just these types of issues.