Square Nut vs. Hex Nut
Square nuts predate hex nuts and still show up where a wide, flat wrench face helps.
| Feature | Square Nut | Hex Nut |
|---|---|---|
| Wrench faces | 4 faces at 90 degrees | 6 faces at 60 degrees |
| Wrench swing | Needs more room to swing | Less swing in tight spaces |
| Torque capacity | Lower before rounding | Higher — more faces to grip |
| Common uses | Antique hardware, strut channel, jigs | Modern general bolting |
| Best for | Where the nut sits in a channel | Standard bolting |
Verdict
Hex nuts are the default — they grip better and need less room. Square nuts earn their keep in channel, restoration work, and fixtures where the nut is captured.