Weld Nut
Nuts · projection weld nut · spot weld nut · weld-on nut
Definition: A weld nut is a nut with projections that are resistance-welded to sheet metal, providing a permanent, captive thread where you cannot reach the back side.
Anatomy
■ Body■ Internal thread
Governing standards: ASME B18.2.6
Common Sizes
| Inch | Metric | Head width | Head height |
|---|---|---|---|
| 1/4-20 | M6 | square 1/2 | 9/32 |
| 5/16-18 | M8 | square 9/16 | 11/32 |
| 3/8-16 | M10 | square 11/16 | 13/32 |
Representative sizes. Full dimensional data lives in the standards listed below.
Grades & Strength
| Grade | Material | Tensile (psi) | Marking |
|---|---|---|---|
| Steel | low carbon steel | — | None |
| Stainless | 304 stainless | — | None |
Materials
- Low carbon steel
- Stainless steel
Pros & Cons
Pros
- Permanent, captive thread
- No access to the back needed
- Strong and vibration-proof
Cons
- Needs welding equipment
- Weld distortion can be an issue
- Cannot be replaced once welded
Typical Uses
- Automotive body panels
- Sheet-metal enclosures
- Appliance chassis
- Captive fastening points
Alternatives & Related
Where to Buy
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FAQ
Weld nut vs rivet nut?
A weld nut is welded on and is permanent and strong, but needs welding. A rivet nut installs with a tool into a drilled hole and is removable — better for thin, coated, or painted panels.
Square or hex weld nut?
Square weld nuts locate better against edges and are common in sheet metal; hex weld nuts suit round bosses. Pick by the joint geometry.