Read about Hollo-Bolt® by Lindapter

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Hollo-Bolt® by Lindapter® Installation is quickly carried out by inserting into pre-drilled steelwork and tightening with a torque wrench. Independent approvals include CE Mark, DIBt, TÜV and ICC-ES seismic accreditation

• Fast, cost saving installation from one side. 

• For square, rectangular and circular hollow sections. 

• High resistance to shear and tension. 

• Patented High Clamping Force design. 

• A range of head types for architectural finishes. 

• CE Mark, DIBt, TÜV and ICC-ES Seismic approval

Hollo-Bolt High Clamping Force Lindapter Hollo-Bolts are available in two versions; the original standard design for general hollow section connections and larger sized High Clamping Force (HCF) for higher strength structural connections

Standard Hollo-Bolt

A typical connection is made by inserting the Hollo-Bolt into the pre-drilled holes of the fixture and hollow section. As the bolt head is tightened, the cone is pulled up the bolt thread, causing the sleeve to expand until the cone locks the sleeve against the hollow section’s inner wall. 

At full tightening torque, a clamping force is established between the fixture and the steel section to form a secure connection. Once installed, only the head and collar are visible.

Hollo-Bolt HCF

By working closely with Structural Engineers and Steel Fabricators, Lindapter identified the need for the larger M16 and M20 Hollo-Bolts to have an increased clamping force suitable for higher strength structural connections. This led to Lindapter’s invention of the High Clamping Force (HCF) design, optimised for superior performance.

The HCF mechanism consists of a special rubber washer that compresses during installation to significantly increase the clamping force between the connecting steelwork, when compared to a product of the same size without the mechanism, thereby reducing displacement

Hollo-Bolt Clamping Force Hollo-Bolts are optimised for structural connections and the larger M16 and M20 sizes feature a High Clamping Force (HCF) mechanism. 

Hollo-Bolt Safe Working Loads The Hollo-Bolt is featured in the BCSA and SCI design guide ‘Joints in Steel Construction – Simple Connections’, please refer to this guide for designing primary structural connections

Hollo-Bolt Characteristic Resistances The values listed in the tables below are to be used when designing bolted connections to Eurocode 3 only, they are not standard safe working loads

Hollo-Bolt Preparation and Installation Please ensure that the holes are drilled into both the fixture and the section according to the drilling guidance below. Please note that the holes are slightly larger than standard bolt clearance holes to accommodate the sleeve and cone.

If you would like more information or support, please contact our dedicated lindapter technical team on or to obtain supported project pricing please contact our Lindapter sales team on or 0121 706 7777

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