Our heavy hex structural bolts use a taller head and wider across flat dimensions than a standard hex bolt, built to handle the high tightening torque of structural steel connections. They pair with heavy hex nuts and hardened washers for a complete bolted assembly. Made in high strength alloy steel with plain, zinc, and hot dip galvanized finishes.

Heavy Hex Structural Bolt, Metric Sizes

What Is a Heavy Hex Structural Bolt?

A heavy hex structural bolt is a high strength fastener with a hex head that is taller and wider across the flats than a standard hex head bolt of the same diameter. The extra head size gives a wrench or socket more bearing surface, which lets the bolt hold up to the higher torque used when clamping structural steel members together. Because the connection often carries significant load, these bolts are almost always installed with a matching heavy hex nut and a hardened flat washer to spread the clamp force evenly.

Heavy hex structural bolts show up in steel frame construction, bridge and platform work, heavy equipment assembly, and any bolted joint where a standard hex bolt would not provide enough bearing surface or strength. They are available fully threaded or with a partial thread and a plain shank, so the correct grip length can be matched to the plate thickness being joined.

Key Features and Benefits

• Larger Head and Flats: extra bearing surface resists rounding and slipping at high installation torque.
• High Strength Alloy Steel: manufactured for use in load bearing steel to steel connections.
• Full or Partial Thread: available in both configurations to match plate thickness and grip length.
• Matches Heavy Hex Hardware: pairs with heavy hex nuts and structural washers for a complete bolted assembly.
• Consistent Metric Sizing: produced to metric standards for a reliable fit across international steel projects.

Materials and Finishes

• Alloy Steel (Plain): for indoor structural connections where corrosion is not a concern.
• Alloy Steel (Zinc Plated): a thinner plated finish for general structural use with light corrosion protection.
• Alloy Steel (Hot Dip Galvanized): a heavier zinc coating for outdoor and exposed steel structures.

Standards Compliance

• DIN 6914, Hexagon bolts for structural steel bolting
• ISO 4014, Hexagon head bolts, product grades A and B, heavy hex variant
• DIN 6915, Hexagon nuts for structural bolting, the mating nut standard

Size Range and Availability

Available in a metric diameter and length range sized for structural steel connections, in alloy steel with plain, zinc plated, and hot dip galvanized finishes.

Related Categories and Products

• Heavy Hex Nut
• Hex Flange Bolts
• Hex Head Bolts (Category)
• Hex Head Cap Screw, Full Thread
• Hardened Thick Flat Washer

Frequently Asked Questions (FAQs)

1. What is a heavy hex structural bolt used for?

It is used in structural steel connections such as beam to column splices, bracing, and other load bearing bolted joints where a standard hex bolt does not offer enough bearing surface or strength.

2. How is a heavy hex bolt different from a standard hex bolt?

A heavy hex bolt has a taller head and a wider across flat dimension than a standard hex bolt of the same diameter, giving it more surface area for the wrench or socket and more resistance to rounding under high torque.

3. Do I need a special nut for a heavy hex structural bolt?

Yes. These bolts are meant to be installed with a matching heavy hex nut so the bearing surfaces and flat sizes line up correctly across the joint.

4. What washer should I use with a heavy hex structural bolt?

A hardened flat washer sized for structural bolting is recommended to spread clamp load evenly and protect the steel surface as the bolt is torqued.

5. Are heavy hex structural bolts available galvanized?

Yes. We stock them in plain, zinc plated, and hot dip galvanized finishes for indoor and outdoor structural applications.

6. Should I choose full thread or partial thread?

Partial thread bolts leave a plain shank that can improve shear performance in thicker joints, while full thread bolts give more flexibility on grip length. Choose based on your plate thickness and engineering requirements.

7. What torque should I use on these bolts?

Installation torque depends on the bolt grade, diameter, and the specific structural application, so always follow the project engineering specification or applicable structural bolting standard.

8. What sizes do you stock for heavy hex structural bolts?

We stock a metric diameter and length range in alloy steel with plain, zinc plated, and hot dip galvanized finishes.