The rolls in this tool cannot be loaded incorrectly. Rotary Tapered Connections use threads that are tapered. The rolls and roll pins on a Cold Rolling tool are tipped slightly to minimize side forces on the rolls and tool components as they travel up that taper. Because the form on a standard API roll is not symmetric, assembly orientation is critical.
When using OEM supplied rolls with the EPL® system (Error Proof Loading® - Patents Pending), rolls CANNOT be loaded backwards. Unlike other tools, you do not rely on an imprecise and often over-looked, visual verification of the 5° skew on the thread form.
The EPL system uses an asymmetric hub system where the hub on one side of the roll is larger than the other. The asymmetric hubs work in conjunction with a step in the roll holder to create Step/Hub interference if the user attempts to load the roll backwards. This eliminates this all too common mistake that can ruin a Rotary Shouldered Connection, and require a connection to be re-cut, or discarded.