would that be because the tension is set too tight on the jaws? are they adjustable? My Renzetti tend's to wobble in the "rotating" part where it attaches to the shaft. Now this is about 6 years old, but still when you pay the kind of money that good stuff costs , it should work perfectly. These companies thankfully , are not building rockets. the equipment is simple in design and should work flawless. I really wish i had my own lathe and some other tools in the garage.