Fasteners are the unseen hardware that holds structures, vehicles, and products together across countless industries. Choosing the right fastener affects safety, durability, and assembly efficiency.
This guide covers the most common types of fasteners, their key specifications, and how to match each to its ideal application.
| Type | Primary Use | Common Materials | Typical Drive or Head Style | Key Strength Feature |
|---|---|---|---|---|
| Machine Screw | Joining parts with a pre-tapped hole or nut | Steel, Stainless Steel, Brass | Phillips, Hex, Torx | High tensile strength with nut |
| Wood Screw | Fastening wood pieces directly | Carbon Steel, Coated Steel | Phillips, Square Drive | Sharp point and aggressive threads for wood |
| Hex Bolt and Nut | Heavy assembly and structural connections | Carbon Steel, Stainless Steel, Alloy Steel | Hex Head with Wrench | High clamping force and adjustability |
| Self-Drilling Screw | Attaching thin metal to wood or metal framing | Zinc-Plated Steel, Stainless Steel | Phillips, Hex Washer Head | Drill-point tip forms hole while screwing |
| Rivet | Permanent joints in sheet metal and composites | Aluminum, Steel, Copper | Solid Shank, Pop Rivet Tool Installed | High shear strength once deformed |
| Anchor | Securing loads into concrete or masonry | Carbon Steel, Stainless Steel, Nylon | Mechanical or Chemical Expansion | Strong pull-out resistance in hardened substrates |
Machine Screws for Controlled Assembly
Machine screws provide reliable fastening where precise hole spacing and threaded inserts are available. They work with a nut or a tapped hole to achieve adjustable clamping force.
Typical Length and Diameter Range
These screws commonly range from small diameters such as #2 to structural sizes like 1/2 inch, with lengths varying to suit material thickness and engagement requirements.
Wood Screws in Structural Framing
Wood screws are designed for high withdrawal strength in solid wood and engineered lumber. Their sharp points eliminate the need for pilot holes in many softwood applications.
Coating for Outdoor Use
Zinc or polymer-coated wood screws resist moisture and corrosion, making them suitable for exterior decks, fencing, and framing projects where long-term exposure is expected.
Hex Bolts for Heavy-Duty Applications
Hex bolts and nuts are fundamental to construction and manufacturing, providing robust and reusable connections for steel structures, machinery, and equipment mounting.
Torque and Preload Control
Using a wrench or socket set, installers can apply precise torque to achieve the necessary preload, ensuring joints remain tight under vibration and load cycling.
Self-Drilling Screws in Metal Framing
Self-drilling screws combine drilling and fastening into one step, streamlining installations on steel studs, purlins, and light-gauge framing.
Point Types and Material Thickness
Different point grades, from nibs to fully self-drilling tips, match specific gauges and thicknesses, so selecting the correct screw reduces installation time and prevents damage to the substrate.
Rivets for Permanent Joints
Rivets create permanent, high-shear joints used in aerospace, automotive, and construction where welding is impractical or prohibited.
Pop and Blind Rivet Families
Pop rivets set with a hand or pneumatic puller, while blind rivets install from one side, making them ideal for assemblies where access to both surfaces is not available.
Anchors for Concrete and Masonry
Anchors transfer loads into concrete, brick, or stone, enabling secure attachment of machinery, handrails, and façade systems.
Mechanical and Chemical Expansion
Mechanical anchors expand through wedging action, while chemical anchors use epoxy or polyurethane to bond the fastener and substrate, offering design flexibility for heavy or precision loads.
Selecting Fasteners for Long-Term Performance
Matching fastener type to substrate, load, and environment is essential for durability and safety.
- Match the fastener material and coating to the environment to prevent corrosion
- Verify thread engagement and embedment depth for the substrate thickness
- Use the correct drive tool and torque settings to avoid stripping or under-tightening
- Consider vibration, thermal expansion, and load type when choosing between screws, bolts, and anchors
- Follow engineering drawings or standards for critical structural connections
FAQ
Reader questions
Which fastener is best for outdoor wooden deck boards?
Coated wood screws with corrosion-resistant finish, such as stainless steel or coated carbon steel, are ideal for outdoor deck boards because they combine good holding power with resistance to moisture and temperature changes.
Can machine screws replace hex bolts in structural connections?
Machine screws are generally not a direct replacement for hex bolts in heavy structural applications, as bolts are designed for higher clamp loads and are used with nuts to ensure controlled tension and safety.
What is the difference between a rivet and a self-drilling screw?
A rivet is a permanent fastener installed by deforming the tail, while a self-drilling screw cuts its own hole during insertion and remains removable, allowing for adjustments or disassembly when needed.
When should I use an anchor instead of a through-bolt?
Choose an anchor when drilling and embedding fasteners into concrete or masonry is necessary and a through-bolt cannot be used, particularly for attaching equipment, railings, or fixtures to hardened substrates.