As the fulcrum, the joint determines the transmission of the force applied to the handles to the effective points: the cutting edges or gripping jaws of the pliers.
The joint axis can be designed as a screw, rivet or forged bolt, depending on the load for which the pliers are designed.
To ensure that pliers with a fixed articulation point rotate without play and still move smoothly, great precision is required when manufacturing all articular surfaces. The connection between the two pliers halves is possible through different designs of the jointconnection.
When the two halves of a pair of pliers are connected by a lap joint, normally used for carpenters' pincers, concreters' nippers and high leverage diagonal cutters, they lie on top of each other without being worked out. This is whay the pliers handles can be made very robust.
When constructing a single joint, both parts of the pliers are half cut out. This way the two pliers handles can be placed inside one another. The outer surface of the rivet area is smooth and not jagged.
Pliers with box joints are particularly resilient. Here, one handle is slotted and the other one is pushed through it. A joint pin mounted on both sides connects the two parts so that both handles are securely guided.
Slip joints allow the gripping jaws of a pair of pliers to be optimally adapted to different workpiece sizes. For this purpose, the jaw opening is enlarged or reduced. This is done by shifting the pliers handles towards or from each other. In order for this to work, either a locking mechanism is unlocked by opening the pliers handles further, or a spring-loaded bolt is disengaged for adjustment. Classic examples of these pliers with this joint are water pump pliers and pliers wrenches.