perno

Perno is a term used in Italian engineering and technical contexts to denote a cylindrical fastener or shaft that serves to join parts or to provide a pivot. In many cases it is equivalent to the English terms pin, dowel, or axle, but the Italian usage often covers a broader range of forms, including hinge pins and through pins used in assemblies.

Pernos come in several common variants. Through pins (perni passanti) run through aligned holes to hold components together while allowing rotation or controlled movement. Dowel pins are typically press-fit into holes to locate parts precisely. Hinge pins are used to connect two elements and permit rotation around the pin’s axis. The exact design—whether the pin is headed or unheaded, threaded or plain, flanged or plain—depends on the application, load requirements, and the desired degree of freedom.

Materials and manufacturing methods vary by use. Common materials include steel (carbon or alloy), stainless steel, brass, and aluminum. Pernos are often turned or ground to precise diameters and tolerances, and may be heat-treated for strength. Retention methods include interference fits, retaining clips, cotter pins, or threaded ends with nuts, depending on how the pin is intended to be secured.

Applications range across automotive, machinery, furniture, and architectural hardware, where pernos serve to constrain motion, align components, or form rotational axes. In technical documentation, the term is used alongside related fasteners such as bolts, screws, and pins, with the exact meaning clarified by context.