Screw

A screw is a threaded fastener used to join components, often with a shaped head for driving. Screws come in many head styles, thread forms and materials for different applications.

A screw fastens parts through a drilled or formed hole. It often matches a nut, a washer or a tapped hole of the same thread. Small screws suit miniature assemblies, sheet metal and plastic housings.

Corrosion-resistant coating is a barrier layer applied to steel screws to slow rusting. It is used where mild corrosion resistance is needed. The coating type and thickness can vary, so check the specification.

Screws are often made in steel, stainless steel, brass, aluminium, plastic or nickel alloys such as Monel, Inconel or Hastelloy. The material choice affects strength, corrosion resistance and electrical properties. Plastic screws suit light loads and insulation.

This is a general guide to checking this kind of part. It says nothing about any supplier's parts.

Ask for a certificate of conformance and a material certificate for the alloy or grade. On receipt, check the thread, head dimensions and coating appearance. Confirm the screw markings or labels match the ordered specification.