This article outlines the five fundamental types of fasteners that hold the manufactured world together. Screws feature a helical thread to tap their own hole in materials. Bolts are used with nuts to clamp parts together and are ideal for strong, removable connections. Rivets are permanent, one-way fasteners installed by deforming their tail. Washers are not fasteners themselves but are essential for distributing load and preventing loosening. Finally, nails provide a quick, simple hold in wood through friction. Each type serves a distinct purpose, with the choice depending on the required strength, permanence, and materials involved.

A fastener is a hardware device that mechanically joins two or more objects together, providing structural integrity while often allowing for disassembly. Essential across construction, manufacturing, and DIY, they withstand forces like tension and shear. Fasteners fall into two main categories: Threaded (rely on helical threads for clamping force) and Non-Threaded (use other joining mechanisms). Key threaded types include bolts, screws (wood, machine, sheet metal, self-drilling, set), nuts, studs, and washers. Major non-threaded types include rivets (permanent), pins (dowel, cotter, clevis, roll), clips/retainers, nails, and anchors. Selection depends on materials, required strength, corrosion resistance, drive type, head style, and the need for disassembly. They are fundamental, versatile components enabling assembly and maintenance.

Choosing the correct snap ring requires key steps: Identify Location: Shaft (external ring, DIN 471/ISO 8750) or Bore (internal ring, DIN 472/ISO 8751/8752). Measure Precisely: Nominal shaft/bore diameter dictates ring size. Design Groove FIRST: Critical groove dimensions (width, depth) must match the chosen ring's specs per standard tables – never guess. Assess Load & Environment: Select material (carbon steel/zinc plated for strength, stainless for corrosion, BeCu for non-spark) and type (e.g., Heavy Duty for high thrust). Use Correct Pliers: Install/remove internal rings (squeeze to compress) or external rings (expand) carefully, avoiding over-deflection. Prioritize Safety: Wear eye protection, inspect rings/grooves, ensure full seating.

"Retaining ring" is the broad term for circular fasteners securing components axially in grooves on shafts or in bores. "Snap ring" specifically refers to a retaining ring subtype featuring lugs or holes for installation/removal using specialized pliers (e.g., DIN 471/472, ISO 8750/8751 standards). Other retaining rings include spiral rings (installed by twisting) and constant-section rings, lacking lugs. Common materials are carbon steel (often zinc-plated) or stainless steel. All types prevent lateral movement of bearings, gears, or assemblies in automotive, aerospace, and machinery. Key difference: Snap rings require pliers; other retaining rings use different installation methods.

Elastic cylindrical pins (spring/roll pins) are hollow fasteners that compress radially in undersized holes, providing vibration-resistant retention via spring force. Types: Slotted: Tubular with slot (Light/Heavy Duty). Coiled (Roll): Spiral coil (Light/HD; best fatigue resistance). Serrated: Slotted with grooves (best axial retention). Materials: Spring-tempered carbon steel (common), alloy steel (HD), stainless (corrosion), brass (niche). Finishes: Zinc plating, oxide, phosphate, passivation. Installation: Drive fully into precise chamfered hole (hammer/press). Selection criteria: Shear loads: Coiled HD strongest Axial loads: Serrated preferred Vibration: Coiled excels Environment: Dictates material/finish Applications: Linkages, shaft components (gears/sprockets), engines/transmissions, automotive/aerospace assemblies, agricultural machinery – anywhere vibration resistance and shear strength matter.