A shear joint by its very nature creates side load, and so it is best to include some kind of guide wall to prevent parts from distorting during the welding process. Energy directors also benefit from use of guide walls. Shear joints are often incorporated into pin-and-socket configurations or weld tabs. Here are some energy director designs: 1 2 3 4 5 6 7 Here are some shear joint designs: 1 2 3 4 To make a ridiculously broad generalization, the more complex joints will require more space in part designs but will often produce stronger results. The double shear in particular should be used with caution. Hot gases and molten material can be trapped under the tongue and produce leaks and wild variations in joint strength unless that area is vented by making one side of the double shear discontinuous around the perimeter of the part.