I would like to add that after I purchased an extruding pug mill, I started throwing without having to center a ball of clay. I find that throwing with coils and slabs so much easier on the wrists, shoulders and back, no strength is needed, just a steadiness as one would generally use after opening the clay. I no longer have to knead my clay either as I put the clay through the pug mill about three times as well as making it softer, likened to squeezing a baby's bottom, which makes it easy to move. I add my clay slop to the boxed clay to make my clay softer. What a thrill it is to create new shapes from this method. No longer am I tied to just round forms.