I created an offset jig to align your RA2 rotary wheel support stand to be perfectly centered on the Chuck rotary jaws. From the photos, you'll notice that the rotary base is aligned to the line in the F1 Ultra base indicating alignement to the chuck. The offset jig is just to take the guesswork out of where to locate those little wheels - no more bending over to make sure your tumbler is riding on both wheels.