Item have no hub step.
U.S. Tsubaki offers the most complete line of QD® and TAPER-LOCK weld-on hubs for insertion and welding to produce “B” style sprockets, sheaves, and other applications without hub protrusion. To provide greater strength for this type of shaft-locking mechanism and to reduce heat distortion caused by welding, these hubs are dimensionally the same as our sprocket items. Special dimensional hubs are available per your specifications on a made-to-order basis. All U.S. Tsubaki hubs are made from steel bar stock (not powdered or sintered metal). The QD and TAPER-LOCK weld-on hubs listed below include appropriate tapered bores and mounting holes.
TAPER-LOCK® is a registered trademark of Rockwell Automation.
QD® is a registered trademark of and is used under license from Tsubaki E&M Co.

All dimensions are nominal values and for reference only