M20 Hollo-Bolt® Structural Expansion Bolt

M20 Hollo-Bolt® Structural Expansion Bolt

Like M16, the M20 Hollo Bolts® are designed to have 3 times the clamping force of smaller diameter hollow bolts. This high clamping force (HCF) mechanism increases the clamping force required of larger diameter bolts in structural applications. 

The Hollo Bolt is a true expansion bolt for structural hollow section (SHS) the blind fastener only requires access to one side to make installation simple.

The M20 requires a 33mm pre drilled hole in adjoining structures and can clamp up to 86mm steel material.

  • 8.8 grade hi tensile steel
  • Hot dipped galvanised
Sub-total: / ex. gst.

National Standards

Design to AS 4100 / NZS 3404 (Steel Structures) and ETA and ICC product certification.


Drill Preparation

Ensure that holes are drilled in both the fixture and the section according to the drilling guidance below. Please note that clearance holes are slightly larger than standard bolt clearance holes to accommodate the sleeve and cone.


  1. Align pre-drilled fixture and section and insert Hollo-Bolt*.
  2. Grip the Hollo-Bolt collar with an open ended spanner.
  3. Using a torque wrench, tighten the central bolt to the recommended torque**.


*Before tightening, ensure that the materials that are to be connected together are touching.

**See product brochure for correct tightening torque. Power tools, such as an impact wrench, may be used to speed up the tightening of the Hollo-Bolt. However, when using power tools, always complete the tightening process with a torque wrench to ensure the correct torque is applied to the Hollo-Bolt.

Hollo-Bolt® and Lindapter® is a registered trademark of Lindapter International.

Product List
SKU Description Availability List Price Pack
More Information
More Information
Delivery SHIPS IN 3 - 5 DAYS
Material Grade 8.8 Hi-Tensile Steel
Coating & Plating Hot Dipped Galvanised (HDG)
Head Type Hexagonal
Driver Type Hex Socket
Technical Information
SKU Size Clamping Thickness Clamping Thickness Clearance Dia. Item
6MHB20-1-HDG M20 x 90mm 12 - 34 mm 12 - 34 mm 33 mm (+2.0 / -0.2) M20 x 90mm Hollo-Bolt HDG
6MHB20-2-HDG M20 x 120mm 34 - 60 mm 34 - 60 mm 33 mm (+2.0 / -0.2) M20 x 120mm Hollo-Bolt HDG
6MHB20-3-HDG M20 x 150mm 60 - 86 mm 60 - 86 mm 33 mm (+2.0 / -0.2) M20 x 150mm Hollo-Bolt HDG