Heavy Duty Bolt

The Heavy Duty Bolt, known as the HD Bolt, was developed as a shorter blind fixing which would offer improved performance when the shear plane being fixed falls across the legs of a standard Blind Bolt

The HD Bolt represents the optimum fixing solution when dealing with heavy weight steel sections. The unique pin locking mechanism and expanding base combine strength with a simple activation process. The only tools necessary are a hammer and spanner, rather than the specialist equipment required when using alternative products. This means that using the Heavy Duty Bolt saves on installation time and expense.

Advantages of the HD Bolt:

  • Quick and simple installation
  • No requirement for an oversized hole
  • 1000 hours of salt spray protection provided by Zinc Flake 1000Hr SSP coating
  • Makes any assembly more efficient
  • Unique pin locking facility

We’re constantly developing new products and devising innovative applications. Please visit our experts guide page to learn more. If you have a specific project in mind, please get in touch using the contact details below. Our team are ready and waiting to explain exactly how Blind Bolts could help.

For detailed information on installation, please view our Heavy Duty Bolt Installation guide, Heavy Duty Bolt Fitting Instructions.

Heavy Duty Bolts


Technical Details

Heavy Duty Blind Fastener

NOTE: All dimensions are in mm unless stated otherwise.

The Blind Bolt Company reserve the right to change these technical details without notice.

Heavy Duty Product Specification High Tensile Steel

Thread Size
Hole Size
(As close to hole
size as possible)
Product Code
Qty Box
Socket Size
Fixing Thickness
1/2 - 13 UNC .500 HDS-5000-2.40 20 3/4 0.200 1.38 2.44
5/8 - 11 UNC .6250 HDS-6250-3.00 20 15/16 0.200 1.38 5.78
3/4 - 10 UNC .7500 HDS-7500-3.40 10 1-1/8 0.200 1.38 5.18

Heavy Duty Performance Data High Tensile Steel - 50,000 PSI Tensile Strength

Thread Size Product Code Stress
Area (IN2)
Bolt Steel Grade Ultimate Tensile
Strength (LBF)
Ultimate Shear
Strength (LBF)
1/2 - 13 UNC 1/2 - 13 UNC .141 High Tensile Steel 7000 7500
5/8 - 11 UNC 5/8 - 11 UNC .226 High Tensile Steel 8000 12000
3/4 - 10 UNC 3/4 - 10 UNC .334 High Tensile Steel 14000 18000


Testing Data Explained

Heavy Duty Bolt Technical Data

The unique and innovative design of the HD Bolt means that certain specific criteria need to be met in order for it to be applied successfully.

Using these criteria means being aware of the way in which the dimensions of each bolt are measured, and these details are set out below.

The image above also offers a pictorial representation of each term. If you still have any questions, please get in touch with us using the contact details at the bottom of the page or by sending us an email by clicking here.

Minimum Fixing Thickness

The minimum fixing thickness is the figure applied to the minimum distance which each bolt is able to fix.

The overall thickness of the materials being clamped is the figure used to make this calculation.

What Is Maximum Fixing Thickness

The maximum fixing thickness is the figure applied to the maximum distance that each bolt is able to clamp.

The overall thickness of the materials being clamped is the figure used to make this calculation.

What Is Depth Clearance

The depth clearance refers to the minimum space required within a cavity wall for the legs on the HD Bolt to deploy effectively.

The measurement has to be noted with great care when fixing into Steel Hollow Sections in order to make sure that the bolt doesn’t reach as far as the opposite section wall before being correctly installed.

What Is Shear Strength Over Thread

The shear strength over thread is the force needed for the bolt to fail if the shear plane produced by the materials being clamped together falls over the threaded section of the bolt.

What Is Tensile Strength

The tensile strength of a HD Bolt is the pull-out force needed for the bolt to fail when a tensile load is acting upon it.


Fitting Instructions

The following videos visually represents the detailed installation of the Heavy Duty Bolt.

HD Bolt Installation Instruction

HD Bolt fitting instructions