Fastening

Fastening joins sheet metal parts or adds threads and attachment points using inserts and rivets, enabling strong, repeatable assemblies without heavy deformation or high heat.

Overview

Fastening in sheet metal fabrication covers installing self-clinching hardware, metal inserts, and rivets to join parts or add durable threads and attachment points. The process uses specialized presses and tooling to embed hardware into punched or laser-cut holes, creating high-strength, flush, and repeatable connections in thin-gauge metal.

Use fastening when you need serviceable joints, robust threads in thin sheet, or to assemble multiple parts without welding. It excels for enclosures, brackets, and panels where you must preserve coatings, avoid heat distortion, or allow disassembly for maintenance. Tradeoffs include added part cost from hardware, stricter tolerance needs on hole size and location, and more setup time. In return, you get consistent alignment, clean aesthetics, and assemblies that can be repaired or modified without cutting or re-welding.

Common Materials

  • Mild steel
  • Stainless steel 304
  • Aluminum 5052
  • Aluminum 6061
  • Galvanized steel

Tolerances

±0.005" to ±0.010" on hole size and fastener location

Applications

  • Electronics enclosures with PEM nuts and standoffs
  • Rackmount chassis with captive hardware
  • Sheet metal brackets with threaded inserts
  • Control panels requiring removable covers
  • HVAC housings and duct flanges joined with rivets
  • Battery boxes and power supply frames with studs and nuts

When to Choose Fastening

Choose fastening when thin sheet needs strong threads, studs, or permanent joints without welding or heavy forming. It suits medium to high volumes where consistent hardware placement, clean appearance, and serviceability matter. Ideal for assemblies that must be field-repairable or where coatings and finishes must remain intact.

vs Cutting

Pick fastening when the main challenge is joining separate sheet metal parts or adding threads, not just defining the flat pattern. Cutting gives you the blank and holes; fastening turns them into a functional assembly with studs, nuts, or riveted joints that handle loads and service requirements.

vs Forming

Use fastening instead of relying only on forming when bends, tabs, and hooks cannot deliver the required strength, alignment, or serviceability. Fastening is better for joining dissimilar materials, attaching removable covers, or adding robust threads where formed features alone would be weak or bulky.

vs Punching

Punching creates the holes and cutouts; fastening uses those features to build the assembly. Choose fastening when those punched holes must carry hardware or permanent joints, not just clearance. It is the right step when you need repeatable hardware placement and load-bearing connections rather than simple openings.

vs Welding (Sheet Metal)

Select fastening over welding when heat distortion, discoloration, or affecting coatings is a concern, or when you need joints that can be disassembled. Fastening is also preferable for very thin sheet, heat-sensitive components, or assemblies requiring precise alignment without post-weld straightening.

vs Hydroforming

Hydroforming shapes complex 3D sheet structures in one piece; fastening joins simpler parts into an assembly. Choose fastening when modular designs, standard flat blanks, and easy replacement of individual components are more important than forming a single seamless shell.

Design Considerations

  • Specify standard self-clinching hardware (series, thread size, material, finish) rather than custom fasteners to control cost and lead time
  • Maintain adequate edge distance and spacing for inserts and rivets; follow fastener manufacturer minimums to avoid sheet deformation and pull-out
  • Call out critical hole diameters and positional tolerances for hardware features; loose or undefined holes cause spin-out and misalignment
  • Design access for press tooling and rivet guns, including clearance around flanges and bends for straight-line approach and backup support
  • Align fastener patterns to common datums and use consistent hole sizes across the part to simplify tooling and reduce setup time
  • Avoid stacking many sheet layers under a single fastener; if unavoidable, specify grip range and stack thickness clearly so hardware is selected correctly