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Type HB Hollo-Bolt™ Flush Fit Head

Hollo-Bolt Flush Fit Head is an expansion bolt that only requires access from one side of the Structural Hollow Section (SHS).

View technical specification Hollo-Bolt Selector


Hollo-Bolt expansion bolts require access to only one side of the Structural Hollow Section (SHS), and offer a faster alternative to welding or through-bolting, enabling contractors to reduce construction time and labour costs. Installation is quickly carried out by inserting into pre-drilled steelwork and tightening with a torque wrench. Also suitable for blind connections where access is available from one side only. The 'Flush Fit Head' version also ensures zero visible protrusion creating an opportunity for architectural design as the head is completely flush with the steelwork and discreet.

Supplied with an innovative installation nut allowing the Flush Fit to be installed without the requirement of specialist skills or equipment.

The fixing is available in sizes M8, M10 and M12.

Features & Benefits

  • Zero visible head protrusion.
  • Fast, cost saving installation from one side.
  • For square, rectangular and circular hollow sections.
  • High resistance to shear and tension.
  • Other head types available.


Click on an approval logo to download the certificate or report.


  • Manufactured from mild steel or stainless steel grade 316.
  • Available with zinc plated or sheraplex finish.
  • Reaction to fire: A1 (Steel)

Durability and corrosion protection:

Corrosivity Class Electroplated Steel Sheraplex Stainless Steel
C1 More than 50 years More than 50 years More than 50 years
C2 More than 20 years More than 50 years More than 50 years
C3 More than 10 years More than 20 years More than 50 years

For C4 and C5 corrosion categories contact us.

Technical Specification

Click to view labelled diagram

Collar Safe Working Loads (5:1 Factor of Safety)
Product Code Countersunk Bolt Ø Length Clamping Thickness Outer Ply Sleeve Outer Ø Ø Installation Nut Tightening Torque Tensile Single Shear
Z B W min t S D A/F
mm mm mm mm mm mm Nm kN kN
HBFF08-1 M8 50 10 - 27 8 13.75 24 19 23 4.0 5.0
HBFF08-2 M8 70 27 - 45 8 13.75 24 19 23 4.0 5.0
HBFF08-3 M8 90 45 - 64 8 13.75 24 19 23 4.0 5.0
HBFF10-1 M10 50 12 - 27 10 17.75 30 24 45 8.5 10.0
HBFF10-2 M10 70 27 - 45 10 17.75 30 24 45 8.5 10.0
HBFF10-3 M10 90 45 - 64 10 17.75 30 24 45 8.5 10.0
HBFF12-1 M12 55 12 - 30 10 19.75 33 30 80 10.5 15.0
HBFF12-2 M12 80 30 - 52 10 19.75 33 30 80 10.5 15.0
HBFF12-3 M12 100 52 - 74 10 19.75 33 30 80 10.5 15.0

  For Characteristic Resistances when designing a connection to Eurocode 3, please refer to DoP No.001

• Hollo-Bolts can be used on a wide variety of steel hollow shape sections. Safe working loads shown are based on use in S275 structural hollow section and are applicable to the Hollo-Bolt only in both tension and shear. Failure of the section, particularly on those with thin walls and a wide chord face, could occur at a lower figure and its strength should be checked by a qualified Structural Engineer.

Faster to Install

No drilling or welding!

Independently Approved

Reasons to choose Lindapter

  • Save time and money

    Save time and money

    Clamping two steel sections together avoids time-consuming welding or conventional drilling and bolting.

  • Safer connections

    Safer connections

    On-site drilling and welding is avoided, removing the need for hot work permits and encouraging safer site conditions.

  • High strength

    High strength

    Lindapter clamps are manufactured from high strength materials to resist high load requirements and harsh environments.

  • Industry leading approvals

    Industry leading approvals

    Lindapter has earned a reputation synonymous with safety and reliability, gaining multiple independent approvals.

  • Adjustable


    Quickly align steel sections by sliding the section into the correct position before tightening the Girder Clamp to complete the installation.

  • Free connection design

    Free connection design

    Lindapter’s experienced Engineers can design a bespoke connection based on your specific requirements free of charge.

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