Pöördepidi

Pöördepidi is a term used in Estonian to denote a pivot pin: a small cylindrical rod that forms a rotating joint between two components while fixing their relative position in other directions. It serves as the axis about which one part can rotate relative to another. Pöördepidi are used in a wide range of mechanical systems, including hinges, linkages, and rotating arms, as well as automotive and industrial equipment. They are typically made of steel or stainless steel, sometimes hardened, and may be finished with zinc plating, black oxide, or other coatings to resist corrosion. Diameters vary, and the length is determined by the design and the distance between the components.

In many applications a pivot pin is simple: a smooth cylindrical rod inserted through aligned holes in the parts; retention may be provided by a threaded end with a nut, a press fit, a retaining clip, or a cotter pin. When selecting a pöördepidi, engineers consider load, moment, misalignment, wear, and corrosion resistance. Tolerances depend on the required fit; common choices include slip fit for easy assembly or light clearance. Some pivot pins include a shoulder to limit penetration and to provide a seat for a bearing or bushing. Variants include clevis pins, shoulder pins, and dowel pins, each with different retention and load characteristics.

Maintenance involves inspecting for wear, elongation, corrosion, and proper alignment, replacing the pin as needed to preserve function.