Bolzen

Bolzen is the German term for a bolt, a mechanical fastener consisting of a cylindrical body with external threading and a head. Bolzen are designed to be inserted through aligned holes and secured with a nut or a tapped thread, creating a clamping force that joins parts. Unlike screws, which often cut into the material, bolts typically rely on a nut or captive thread for the fastening.

Common bolt types include hex bolts (with a hexagonal head), carriage bolts (with a domed head and square neck), shoulder bolts (also called guide pins), and anchor bolts (used to attach components to concrete). Finishes and head styles vary, such as flange bolts (with an integrated washer-like flange), eye bolts, and U-bolts. Thread types include metric coarse or fine pitches and inch-based UNC or UNF standards.

Bolzen are manufactured from materials such as carbon steel, alloy steel, stainless steel, brass, or titanium, with heat treatments to increase strength. Standards cover dimensions and tolerances, including ISO metric bolts (ISO 4014/4017), DIN equivalents (DIN 931/933), and English-language standards like ANSI/ASME B18.2.1. Property classes indicate strength (for example, metric bolts 8.8 and 10.9). Finishes include zinc plating, hot-dip galvanizing, black oxide, and phosphate coatings.

They are used across machinery, automotive, construction, electronics, and consumer products. Proper use requires selecting the correct diameter, length, and thread, and applying appropriate torque or preload. Compatibility with nuts, washers, and lubricants is important to achieve reliable clamping and to prevent galling or corrosion over time.