I started this thread because I wanted clarification. Even though the Flex 3401 spins at MAX 4800 OPM, it's the *forced rotation* that makes it so effective. I didn't realize how much forced rotation plays a factor.
Dave can you tell us more about these different figures and how they should be referenced.
The 3401 only spins at a max of 480 R.P.M. , To see the big picture here one would need to temporarily abandon the thought of O.P.M. because they just don't fully apply in what is creating the correction with the 3401. This can be a bit tricky to explain the mechanics of this tool in a forum but I'll try.
The 3401 has a steel gear driven shaft that comes out of the gearbox that spins at 480 R.P.M. when I say gear box I don't mean the plastic gears above the backing plate.
Mounted to the end of that steel shaft is a metal disc of sorts which has a threaded hole in the disc on an eccentric or offset if you will. The backing plate is attached through a bearing on the backing plate with the hex (allen) screw. This mounting location on the disc is the only thing that is actually orbiting. This sounds a bit contradictory because since the center of the backing plate is orbiting obviously so is the entire backing plate. and this is where the spirograph comes into play.
The drive or central output shaft is what creates the forced rotation. The disc with the threaded hole in it creates an eliptical orbit but it is still 480 eliptical orbits. (this is why I say O.P.M. doesn't fully apply with this type of tool) This is where it gets tricky, the backing plate gear (which has less teeth than the bell housing gear) and the bell housing gear only mesh in a small area at any given time. (maybe 33% of the teeth)
It is the action of these plastic gear teeth meshing during this eliptical orbit that creates the 20 strokes per 1 revolution. (see the design made by the spirograph toy)
20 strokes x 480 revolutions per minute = 9600 strokes. So the backing plate is actually stroking back and forth 9600 times combined with the backing plate rotating 480 times, this all occurs within 1 minute at speed setting #6. That makes for some pretty good correction and the plastic gears only have the strain caused by the drag of the pad against the paint which isn't much.
As far as power goes it would be like measuring the horse power at the wheels on a car, in that is is geared power. I think if I tried to grab the backing plate and pad and stop it with my hand I would have some broken or at least injured fingers. So this tool has tremendous power. much more power than that of a rotary because it is geared to spin at only 480 R.P.M. but that power has nothing (other than the ability to apply downward pressure) to do with the rate of correction.
Like I said it is a bit tricky to explain in written words, hopefully this will shed some light on your understanding of the tool. If you go to Flex's website and look at the PDF catalogs you will clearly see that they are a serious power tool manufacturer with high quality tools