DTS 400EQ question. Shaky at low speed

[greenbayguy]

Hello ya'll,

I recently picked up the floor model of a DTS400EQ from my local guy. Smooth as expected, similar to my 150/3. Smooth in 1-speed. I should note, I usually run my sanders in low speed with the vac on turtle -- personal preference. At the time of my purchase, he ordered me a new one deliverable in a couple weeks.

Couple weeks later I picked up the new one. It is very jumpy in speeds 1-4, and gets a little better in 5-6. Basically, not at all a pleasure to use, unlike the floor model and the 150/3. I have several of the products, and with my prior DTS400EQ experience, I think I have a reasonable expectation of how this sander should feel. No I do not press down, yes I let the sander do the work. I am ruling out operator error.

So my question is: is this sander going through a "break-in" period? Is this how it should feel out of the box? Don't really want to deal with the hassle of returning it if I don't have to.

Subquestion: I tried the RO150 a while back and it was the same kind of jumpy. It performed exactly like the Fine Woodworking review suggested. Putting the pieces together, I bet FWW received a new one too... maybe not broken in. Since there experience was so different than much of what I see posted here, it furthers my "break-in" hypothesis. Does the jumpiness subside with the RO150?

Thank you!

 

[Brice Burrell]

Since you know about the break in period this shouldn't be a big surprise.  The small small sanders can particularly jumpy before break in and this especially true at low speeds.  I find the small sander like the DTS and RTS work best for me at full speed.  I see no great benefit to lower the speed on these sanders.

The Rotex sander don't really suffer much in the way of symptoms from the break in period.  A jumpy Rotex is in all probability user error.   

 

[AlexThePalex]

The shakyness is what you get when running any sander at low speed. So it's probably amplified on a sander that's new and needs to be broken in. I myself can't on earth imagine why you would want to lower the speed of a sander. There's no advantage and a heap of disadvantages. 

 

[Administrator_JSVN]

If you're sanding wood, it's recommended to turn the speed setting to 6. Basically, you need to give the sander enough power to overcome the friction of the material. Lower settings, 4 and below, would be for much smoother materials or sanding a finish.

It takes several hours for the brushes to become fully seated when the sander is new.  During this time, you are not getting the full power from the motor.