The TorsionBellT spool used on all Models designated as 225 or 275, is a unique KELLO-BILT design, fabricated from 3/8" steel plate cold formed into bells of different diameters, of which one of each is welded to either end of a heavy schedule pipe. The complete piece is then machined to be true and concave at one end and convex at the other. 

When assembled on the gang shaft, the small bell is on the concave side of the disc blade and the large bell is on the convex side. When the gang is tightened, tension applied to the blades acts to keep the entire assembly tight. The fabricated steel construction withstands rock damage and crushing.