Global Truss Coupler Pin 2, S45C Steel

The coupler pin is the part that actually carries the joint. Global Truss machines this one from S45C steel, a medium-carbon grade chosen for the shear strength a truss joint needs, and it drives through the coupler to lock two truss sections into one run.

The threaded end is M8 and 18 mm long, and Global Truss specifies a tightening torque of 10 to 12 N/m for the nut. Use a torque wrench and hit the number: an undertightened joint works loose over a show and an overtightened one damages the thread. Each pin weighs 1.1 lb. Global Truss part number CP0209.