This is one of those things that I am reluctant to admit but when I finally do mention it and someone is also surprised or has had the same experience I say to myself, once again, "Welcome to the human race!"
Until today I did not know a ball winder such as the one shown could wind wool into a ball bigger than the base of the cone or whatever it is called. So until now the purple size is as big as I ever wound.
Today when I had wound about 3/4 of the skein of yellow (it's intended to become flowers for on a tree trunk outside one of the Knitting Cafe's) and not wanting to end and have to wind another ball which would be very small, I decided to just keep on winding but pay extra attention so the yarn didn't scoot underneath and get all tangled (voice of experience speaking here). And the ball just kept getting bigger and bigger but still winding nicely. Whew and wow! I got the whole skein into that one ball.
On further reflection and observation it seems to me that the size of the ball is not limited by the size of the base of the cone (owiic) but the distance between the cone base and the yarn guide so, with a bit of an adaptation, HUGE balls of wool could be wound. Why would we want to? Oh, because we could, I guess. And those nicely wound balls look so neat sitting around the house as expression of the art of playing with fibre.
I do have one quibble with that wool winder – I have to manually hold the yarn guide away from the winder or it collapses or slides in toward the winder and then collapses. I suspect I am not positioning something correctly and am more than willing to be embarassed if someone points out how to correct this.