Key issues in stud welding include incomplete fusion from contamination or incorrect settings, excessive melt-out due to high heat, and porosity from moisture or damaged ferrules. Other problems are uneven weld fillets from misalignment and burn-through on thin materials. Most defects are preventable through meticulous cleaning of the workpiece and stud, using correct and well-maintained equipment, and strictly following the manufacturer's recommended welding parameters for current, time, and polarity.

A weld stud is a fastener welded onto a metal surface to create a strong, threaded attachment point without needing backside access. Primarily installed using capacitor discharge (for thin materials) or drawn arc (for heavy-duty) methods, they eliminate the need for drilling holes. Common types are threaded or unthreaded, made from materials like steel, stainless steel, or aluminum, often with finishes like zinc plating for corrosion resistance. Their key advantage is providing a permanent, high-strength stud efficiently. They are widely used in construction, automotive manufacturing, shipbuilding, and appliances for attaching everything from panels and insulation to electrical components.

A weld nut is a fastener specially designed to be permanently welded onto a metal surface, providing a strong, reliable threaded anchor point. Typically made from low carbon or stainless steel, they come in types like projection, pilot, and flange nuts, suited for different applications. Installed via resistance or arc welding, they are essential in industries like automotive manufacturing, appliances, and construction, where creating durable threads in sheet metal or frameworks is critical.

A set screw is a headless fastener that secures components, like gears to shafts, by applying compressive force. Key types are flat, cone, cup, cylindrical, and spherical points, each offering different gripping and marring properties. Typically made from carbon or stainless steel with various finishes, they feature drive types like hex sockets for high torque. Proper installation, including using a pre-drilled dimple for certain points and correct tightening torque, is crucial for a secure, vibration-resistant hold. They are essential in power transmission, automotive, and manufacturing applications.

This article explores the vast variety of nuts, essential fasteners that pair with bolts. Key types include standard hex nuts, vibration-resistant lock nuts (like nylon insert), load-distributing flange nuts, hand-tightenable wing nuts, and specialized T-nuts and rivet nuts for blind applications. Material choice—from carbon steel and stainless steel to brass and nylon—is critical for strength, corrosion resistance, and suitability to environments like automotive, aerospace, or marine applications. Selecting the correct nut type and material is fundamental to ensuring a secure, durable, and functional assembly for any project.