Pins

Pins are slender fasteners used to hold parts together, align components, or permit easy disassembly. They range from tiny sewing pins to heavy dowel pins, and they appear in mechanical assemblies, electronics, textiles, and everyday items. Pins are manufactured in a variety of materials, shapes, and sizes to suit different applications.

Mechanical pins include straight pins for assembly, dowel pins for precise alignment, and roll pins (spring pins) that lock into a hole by deformation. Cotter pins and split pins secure bolts or other fasteners and are bent to prevent withdrawal. Hairpin, hitch, and quick-release pins are designed for rapid removal or interchange in equipment.

Textile and clothing pins such as sewing pins and dressmaker pins are used to hold fabric in place during cutting or stitching. Safety pins are spring-steel pins with a clasp that protects the point and can be temporarily fastened to fabric, garments, or accessories.

Electronic pins are the conductive protrusions that connect components in circuits. They appear on integrated circuits, pin headers, and connectors. Spring-loaded pogo pins are used as test probes, while drive pins or alignment pins locate parts during assembly.

Materials include steel, stainless steel, brass, aluminum, and plastic, with coatings such as zinc or nickel for corrosion resistance. Sizes and tolerances vary by type, from fine machine pins to larger structural dowel pins. The term "pin" thus covers a broad family of products used for fastening, alignment, temporary holding, and electronic interconnection.