Coupling Nut vs. Hex Nut (for Joining Rods)
A hex nut fastens one end; a coupling nut joins two rod ends together.
| Feature | Coupling Nut | Hex Nut |
|---|---|---|
| Length | Long (2–3x a hex nut) | Short |
| Purpose | Joins rods end to end | Clamps a single joint |
| Engagement | Both ends fully threaded | One side |
| Best for | Extending hanger rods | Standard bolted joints |
Verdict
To extend or join threaded rod, use a coupling nut. For ordinary bolting, a hex nut is the tool.