Square Head Bolt (DIN 478 / DIN 479)
Square head bolts have a four-sided head, used historically before the hex head became standard. They remain in use today in specific machinery applications, restoration work, and architectural ironwork. The square head can be wrenched with an open-end wrench in tight spaces where a hex socket cannot fit.
Specifications
| Standards | DIN 478, DIN 479 (square head, square neck) |
|---|---|
| Diameter Range | M6 – M30 |
| Material | Carbon steel, Stainless |
| Surface Finish | Plain, Zinc plated, HDG, Black oxide |
| Application | Machinery, valve handles, antique restoration, architectural |
Frequently Asked Questions
Why are square head bolts still used?
Square heads provide better wrench grip on four flats versus hex's six, and can be tightened with adjustable wrenches more securely. They are still specified in some heavy machinery, valve assemblies, and any application where the visual or mechanical heritage of the connection matters.
Need a quote on Square Head Bolt?
Send us your specifications, target quantity, and destination port. We will respond within 24 hours with sourceable options and indicative pricing.
Get a Quote