Flange Nut vs. Hex Nut
A flange nut is a hex nut with a built-in washer face.
| Feature | Flange Nut | Hex Nut |
|---|---|---|
| Washer | Built-in serrated or smooth flange | None — separate washer needed |
| Parts count | One piece | Two pieces (nut plus washer) |
| Load spread | Built in | Only if you add a washer |
| Anti-loosen | Serrated flange resists vibration | Pairs with a lock washer |
| Best for | Automotive, high-volume assembly | General bolting |
Verdict
Flange nuts save a part and resist loosening on oversize or slotted holes. Use a hex nut plus washer where you need a specific washer type or finish.