Just checked the new one I bought. 1/4" wobble at the end of the extension. Totally unsat. Will contact Clam.
I investigated a little more and found that the welding between the 2 diameters of tubing was OK and true. The hole where it attaches to the clam adapter is off. When I don't put the screw in it runs true. When I use either the wing nut or the socket head screw I get a tremendous wobble at the end of the extension. Without the extension my auger runs true.