Screwfastened

Screwfastened describes a method of joining two or more parts by means of screws and threaded fasteners. In a screwfastened joint, a screw or set of screws engage internal threads in a tapped hole or a nut, generating clamping force that holds the parts together through friction and shear resistance. The joint is typically disassemblable, allowing maintenance and reconfiguration.

Common components include machine screws and wood screws, as well as self-tapping and self-drilling screws, bolts paired with nuts, and washers. Materials used for screwfastened assemblies include steel, stainless steel, aluminum, and brass. Thread forms span metric and imperial systems, with standards such as M, UNC, and UNF. Driving heads vary, including Phillips, slotted, Torx, and hex designs.

Design considerations involve adequate thread engagement length, precise hole alignment, and proper preload to prevent loosening without overstressing the material. In applications subject to vibration or dynamic loads, locking mechanisms are used, such as thread-locking compounds, lock washers, nylon-insert lock nuts, prevailing-torque fasteners, or adhesive methods. Material compatibility and corrosion resistance are important to prevent galvanic effects.

Advantages of screwfastened joints include ease of assembly and disassembly, reusability, and cost-effectiveness for moderate loads. They support modular design and straightforward maintenance. Limitations can include loosening under cyclic loading, reliance on accurate tightening procedures, and potentially lower stiffness or strength compared to welded or bonded joints for certain high-load applications.

Screwfastened joints are widely used in machinery, consumer electronics enclosures, furniture, automotive assemblies, and other sectors, with standards from ISO, DIN, ANSI/ASME, and JIS guiding dimensions and tolerances.