Fastening

Sheet metal fastening mechanically joins parts or adds threaded features using inserts or rivets, enabling serviceable, low-heat assemblies with repeatable strength.

Overview

Fastening in sheet metal fabrication adds mechanical joints or threaded attachment points without melting the base metal. Common methods include self-clinching inserts (PEM-style nuts, studs, standoffs) and riveting, which lock components together through deformation and clamping.

Choose fastening when you need quick assembly, field serviceability, mixed-material joints, or heat-sensitive parts where welding distortion and HAZ are risks. It’s also a clean way to add durable threads in thin gauge sheet where tapping would strip.

Tradeoffs: joints need access for installation tools and often require overlap, holes, and edge distance that consume real estate. Joint strength depends on sheet thickness, material hardness, and correct hardware selection; pull-out/spin-out can occur if the parent material is too thin or too hard/soft for the fastener. Fasteners add BOM items and labor, but usually reduce rework risk versus heat-based joining.

Common Materials

  • CRS Steel
  • Stainless Steel 304
  • Stainless Steel 316
  • Aluminum 5052
  • Aluminum 6061
  • Galvanized Steel

Tolerances

±0.005"

Applications

  • Electronics enclosure assembly
  • Rack-mount chassis with removable panels
  • HVAC duct and cabinet joints
  • Appliance brackets and subassemblies
  • Battery pack housings with service access
  • Automotive sensor and ECU brackets

When to Choose Fastening

Fastening fits parts that must be assembled and disassembled, require reliable threads in thin sheet, or can’t tolerate weld heat and distortion. It works well from prototypes through production when you can design in tool access, hole features, and consistent joint geometry. It’s also a good choice for mixed materials or coated parts where preserving surface finish matters.

vs Cutting

Choose fastening when the requirement is assembly—joining multiple cut blanks into a rigid structure or adding durable threaded attachment points. Cutting defines the flat pattern; fastening turns the kit into a functional, serviceable assembly.

vs Forming

Choose fastening when bends alone won’t create the needed strength, access, or attachment features, or when you need removable interfaces. Forming creates geometry; fastening adds joints and hardware features that can be repeated across configurations.

vs Punching

Choose fastening when you need the punched holes to do more than locate—e.g., accept clinch nuts/standoffs or rivets for structural or threaded connections. Punching is often the precursor; fastening delivers load-bearing joints and assembly-ready interfaces.

vs Welding (Sheet Metal)

Choose fastening when you need low distortion, minimal cosmetic cleanup, and easy service disassembly. Fastening avoids HAZ issues and works better on coated/painted parts, but it requires hardware, access, and joint real estate.

vs Hydroforming

Choose fastening when the part is better built as multiple simpler shells/brackets rather than a single complex formed body. Fastening lets you modularize and revise subcomponents without requalifying an entire formed tool set.

Design Considerations

  • Provide tool access for press insertion or riveting (straight-line access, adequate throat clearance, and space around the feature)
  • Follow fastener supplier rules for minimum sheet thickness, hole size, and material hardness to prevent spin-out and pull-out
  • Keep fasteners away from edges and bend radii; reserve edge distance and avoid placing hardware in bend zones
  • Standardize on a small set of hardware types and thread sizes to reduce BOM cost, installation time, and quoting ambiguity
  • Call out finish sequence (install before/after plating or powder coat) to avoid cracked coatings or masked threads
  • Dimension critical interfaces to the installed fastener feature (thread location, standoff height) rather than only to the pre-fastener hole