westmo - 8/20/2013 16:35 Discovered a crack in the rear rock shaft on my 750 drill so I pulled the tube out, cut it, put a piece inside and welded back together. However, in spite of my efforts I didn't get it welded back exactly square and just wondering if that will matter no more than the tube rotates. Also, bought the center castings and bearing but when I install the three pieces and tighten the bolts I can't turn the bearing. (With or without the tube). Is there a torque spec or some shims to keep from pulling up too tight. Appreciate any thoughts.