fusos

Fusos, or parafusos in Portuguese, are a family of fasteners consisting of a threaded shaft and a head. They are designed to join two or more parts by engaging threads in a tapped hole or with a nut, converting rotational motion into linear clamping force. Variants include screws intended to be driven into preformed material and bolts used with a nut. Self-tapping screws can form their own thread in certain materials.

Common head types include flat, pan, round, oval, and countersunk, with drive styles such as slotted, Phillips, Pozidriv, Torx, and hex. The term covers a wide range of designs adapted for different materials and loads, including wood screws, machine screws, and drywall screws. Materials vary from carbon steel and stainless steel to brass and aluminum, often with finishes like zinc plating, galvanization, black oxide, or nickel for corrosion resistance and aesthetics.

Standards and sizes are global and material-dependent. Metric screws use ISO thread standards (for example, M6 x 1 denotes a 6 mm diameter and 1 mm pitch), while many regions also use UNC/UNF systems. Length is specified to match the engaged material, and strength is indicated by grades or classes.

Manufacturing and installation typically involve cold forming or machining for the threads. Proper tool selection, correct torque, and compatible tolerances are essential to avoid stripping or damaging the threads. Pre-drilling or tapping may be required, depending on the screw type and material.

Applications of fusos span furniture, machinery, automotive, electronics, and construction, reflecting their essential role in joining components across diverse industries.