Rotex 150 unsure if operating properly

[matsukaze]

hi guys I have a rotex 150 Works amazing as a grinder. But unsure if the random orbit is functioning properly.
On my brushless 125 the disc rotates as it sands. Actually hard to stop it.... unsure if I have had.
But the rotex does not rotate very consistant ly. On high speed (6) with higher grits 180,220, it will rotate with the orbit if you use the lightest of pressure. But say 60 grit on 1 or 2 speed, Does not spin. Honestly not seeing it perform as a finish sander very well at all.
I am hoping it may be defective. As I want  it to perform.  Can any one tell me how theirs operates? Or if mine sounds out of wack?
Many thanks.
Correy

 

[Gregor]

In fine sanding mode the pad is able to turn freely (rotation isn't prevented) but it shouldn't spin but more turn and the rotation shouldn't be excessive.

Increased pressure likely increases what you experience - but the Rotex 150 IMHO dosn't need pressure as the weight of the machine is enough (at least in my experience). Don't try to push it, just guide it - took me a while to figure that out. I now have one hand on the front knob to guide it, the other at the very back just to support it to keep the pad from tilting.

Also: Dust collection could be a factor, have you tried to vary (meaning reduce) the suction? Or to turn the speed down just slightly, stopping it from possibly hitting a resonance frequency?

Finally: As "Three tools in one for coarse sanding, fine sanding, and polishing " it's not a specialized finish sander.
But in my experience close enough most of the time.

 

[matsukaze]

Hi Thanks Gregor,  Yes you describe it the same as mine. Just a bit perplexed as the 125 sander ETC(?) ( sorry not in the shop right now) has a very positive rotation as well as eccentric orbit. Isn't this the essence of Random Orbit? I lower the vac  power when sanding too.
It seems to finish fine enough.  I do not think the 5mm eccentric is good for clear coat, The finish with the 125/3( or probably any x/3) is much nicer. As should be.
Just gets me it does not have a positive rotation. Design flaw?
We're debating if we should keep it. I might go 150/3 as we don't "grind" much. and our surfacer leaves pretty spectacular finish. Usually just start at 220 most of the time.
Anyone else see it weird it doesn't spin?

 

[Gregor]

Forgotten to add this, a nice video about the topic:

 

[Mike Goetzke]

Hi Thanks Gregor,  Yes you describe it the same as mine. Just a bit perplexed as the 125 sander ETC(?) ( sorry not in the shop right now) has a very positive rotation as well as eccentric orbit. Isn't this the essence of Random Orbit? I lower the vac  power when sanding too.
It seems to finish fine enough.  I do not think the 5mm eccentric is good for clear coat, The finish with the 125/3( or probably any x/3) is much nicer. As should be.
Just gets me it does not have a positive rotation. Design flaw?
We're debating if we should keep it. I might go 150/3 as we don't "grind" much. and our surfacer leaves pretty spectacular finish. Usually just start at 220 most of the time.
Anyone else see it weird it doesn't spin?

Maybe more experienced can speak up but don't think it's normal for your ETC to spin continuously.