the standard

Blind Bolt

Thanks to the unique flexibility of the Blind Bolt we are constantly finding new areas where the product can save time and money, as well as increasing our range of sizes to suit your requirements.

The Blind Bolt brings exceptional qualities to the market in that it has transcended the first generation of blind fixings and fasteners become a product that is widely utilised throughout the construction industry. There aren't many fixing products which can change the way designers and architects think, but we can honestly state that about our blind bolts.

No longer is fixing into a girder cavity or box section a problem. The Blind Bolt has provided a solid solution whilst also reducing costs, in most cases. The Blind Bolt is now being used in areas where never expected and we are sure there are many more uses for the system.

For detailed information on installation or removal, please view our Installation and removal guide Blind Bolt Fitting Instructions

Please visit our News page for information about new products and applications. Alternatively please contact us using the details below to discuss your projects and how we could help.

Blind Bolt Fixing

Find Your Standard Blind Bolt

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Blind Bolt Thickness Diagram
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Blind Bolt

Technical Data Explained

Blind Bolt Testing Terms

NOTE: All dimensions are in mm unless stated otherwise.

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

Blind Bolt Product Specification Geomet 500B - Property Class 10.9

Product Code Bolt Size Box
Qty
Hole
Diameter
Fixing
Thickness
Min Max
Anchor
Clearance
Depth
Clearance
Minimum
Hole Centers
BB0850DTASM M8 x 50 50 9 9 24 19 25 20
BB1060DTASM M10 x 60 40 11 10 30 23 30 20
BB1095DTASM M10 x 95 20 11 25 65 23 30 20
BB10130DTASM M10 x 130 20 11 55 100 23 30 20
BB1270DTASM M12 x 70 20 13 12 35 26 35 25
BB12120DTASM M12 x 120 25 13 30 85 26 35 25
BB12180DTASM M12 x 180 20 13 80 140 26 35 25
GBB1475DTASM M14 x 75* 20 15 14 35 32 38 32
GBB14125DTASM M14 x 125* 20 15 28 82 32 38 32
GBB14185DTASM M14 x 185* 20 15 75 142 32 38 32
GBB1690DTASM M16 x 90* 20 17 13 43 36 43 35
GBB16130DTASM M16 x 130* 15 17 40 75 36 43 35
GBB16180DTASM M16 x 180* 10 17 55 125 36 43 35
GBB20110DTASM M20 x 110* 10 22 21 56 44 56 48
GBB20140DTASM M20 x 140* 8 22 21 86 44 56 48
GBB20180DTASM M20 x 180* 10 22 80 120 44 56 48
GBB20250DTASM M20 x 250* 10 22 130 185 44 56 48
GBB24130DTASM M24 x 130* 5 26 21 66 53 64 60
GBB30140DTASM M30 x 140* 5 32 27 60 65 72 75
* We strongly recommend the use of our safety gauges when installing these bolts

Blind Bolt Product Specification - Hot Dip Galvanised - Property Class 10.9

Product Code Bolt Size Box
Qty
Hole
Diameter
Fixing
Thickness
Min Max
Anchor
Clearance
Depth
Clearance
Minimum
Hole Centers
GBB1690HDG M16 x 90* 20 17 13 43 36 43 35
GBB20110HDG M20 x 110* 10 22 21 56 44 56 48
GBB24130HDG M24 x 130* 5 26 21 66 53 64 60
* We strongly recommend the use of our safety gauges when installing these bolts

Important Note

The below tension resistances make no allowance for the deformation or yield of the connected parts. An appropriate design model for connections in hollow sections can be found in Joints in Steel Construction: Simple Connections.

High TensileGeomet 500B Blind Bolt Design to BS 5950-1

Diameter

Tension Capacity

Shear Capacity
Over Thread

Shear Capacity Over Slot

Bearing Capacity
in 10mm Plate

Recommended
Tightening
Pt (kN) Ps, thread (kN) Ps, slot (kN)  S275
Pb, (kN)

 S355
Pb, (kN)

Torque (Nm)
M
8
9.8 14.6 7.9 20.7 24.8 15
M 10 14.1 23.2 15.8 27.6 33.0 24
M
12
22.4 33.7 22.0 32.2 38.5 30
M
14
34.8 46.0 29.0 36.8 44.0 40
M 16 38.8 62.7 43.0 46.0 55.0 50
M
20
71.4 97.9 63.4 55.2 66.0 65
M 24 116.7 141.0 87.8 64.4 77.0 75
M
30
174.5 224.0 137.2 80.5 96.3 85
These values are suitable for design to BS 5950-1 and can be used without further reduction for comparison to factored loads. Bearing resistances for different plate thicknesses can be calculated by scaling the values in proportion to the thickness, but should only be used where the distance from the centre line of the hole to the end of the plate is greater than 2d.Combined tension and shear should satisfy the following equation:
tensionshear top ss technical data Blindbolt UK

Important Note

The above tension resistances make no allowance for the deformation or yield of the connected parts. An appropriate design model for connections in hollow sections can be found in Joints in Steel Construction: Simple Connections.

High Tensile Geomet 500B Blind Bolt Design to BS EN 1993-1-8

Diameter Tension
Resistance
Shear
Resistance
Over Thread
Shear
Resistance
Over Slot
Bearing Resistance
in 10mm Plate
Recommended
Tightening
Torque

Ft, Rd (kN)

Fv, Rd thread (kN)

Fv, Rd Slot (kN)
S275
Fb, Rd(kN)
S375
Fb, Rd(kN)

(Nm)
M 8 9.8 14.6 9.1 65.6 75.2 15
M
10
14.1 23.2 19.0 82.0 94.0 24
M 12 22.4 33.7 26.4 98.4 112.8 30
M
14
34.8 46.7 29.0 114.8 131.6 40
M
16
38.8 62.7 49.1 131.2 150.4 50
M 20 71.4 97.9 76.1 164.0 188.0 65
M
24
116.7 141.0 105.4 196.8 225.6 75
M 30 174.5 224.0 164.6 246.0 282.0 85
These are design values for use with BS EN 1993-1-8, and a partial safety factor of γM2 = 1.25 has already been applied. Bearing resistances should be calculated from BS EN 1993-1-8, Table 3.4, taking d as the nominal diameter of the bolt.

These design resistances are suitable for design to BS EN 1993 and can be compared directly with design loads. The quoted bearing resistances assume k1 = 2.5 and αb = 1.0. For different arrangements the bearing resistance should be calculated using the expression in Table 3.4 of BS EN 1993-1-8, with d as the nominal diameter of the blind bolt.

Combined tension and shear should satisfy the following equation:

ss calc bot technical data Blindbolt UK

Important Note

The above tension resistances make no allowance for the deformation or yield of the connected parts. An appropriate design model for connections in hollow sections can be found in Joints in Steel Construction: Simple Connections.

Stainless Steel Blind Bolts Technical Data

Blind Bolt Product Specification Stainless Steel A4-70

Product Code Bolt
Size
Box
Qty
Hole
Diameter
Fixing
Thickness
Min Max
Anchor
Clearance
Depth
Clearance
Minimum
Hole Centers
BB0850A4ASM M8 x 50 50 9 9 24 19 25 20
BB1060A4ASM M10
x 60
40 11 10 30 23 30 20
BB1290A4ASM M12 x 90 20 13 12 55 26 35 25
GBB16100A4ASM* M16
x 100
20 17 13 53 36 43 35
* We strongly recommend the use of our safety gauges when installing these bolts

Stainless Steel Blind Bolt Design to BS 5950

Diameter Tension Capacity
Pt (kN)
Shear Capacity
Over Thread
Ps, thread (kN)
Shear Capacity Over Slot
Ps, slot (kN)
Bearing Capacity
in 10mm Plate
Recommended
Tightening
Torque (Nm)
        S275
P
b, (kN)
S355
Pb, (kN)
 
M 8 5.3 10.3 6.5 20.7 24.8 15
M
10
12.7 16.2 11.1 27.6 33.0 22
M 12 21.4 23.6 15.4 32.2 38.5 28
M
16
42.8 44.0 30.1 46.0 55.0 45
These capacities are suitable for design to BS 5950-1 and can be compared directly with factored loads. Bearing resistances for different thicknesses can be
calculated by scaling the values given in proportion to the thickness, but should only be used when the end distance is greater than 2d.Bolts subject to combined tension and shear should satisfy the following expression:

tensionshear top ss white technical data Blindbolt UK

Important Note

Note that the above tension capacities make no allowance for the deformation or yield of the supporting parts.  An appropriate design model for connections in hollow sections can be found in Joints in Steel Construction: Simple Connections.

Stainless Steel Blind Bolt Design to BS EN 1993

Diameter Tension Resistance
Ft,Rd (kN)
Shear Resistance
Over Thread
Fv,Rd thread(kN)
Shear Resistance
Over Slot
Fv,Rd slot (kN)
Bearing Capacity
in 10mm Plate
Recommended
Tightening
Torque (Nm)
        S275
Fb,Rd(kN)
S355
Fb,Rd(kN)
 
M 8 5.3 12.3 7.8 65.6 75.2 15
M
10
12.7 19.5 13.3 82.0 94.0 22
M 12 22.0 28.3 18.4 98.4 112.8 28
M
16
42.9 52.8 36.1 131.2 150.4 45
These design resistances are suitable for design to BS EN 1993 and can be compared directly with design loads. The quoted bearing resistances assume k1 = 2.5 and αb = 1.0. For different arrangements the bearing resistance should be calculated using the expression in Table 3.4 of BS EN 1993-1-8, with d as the nominal diameter of the blind bolt.

Bolts subject to combined tension and shear should satisfy the following expression:

ss calc bot 281 29 technical data Blindbolt UK

Important Note

Note that the above tension capacities make no allowance for the deformation or yield of the supporting parts.

Blind Bolt

Testing Data Explained

Blind Bolt Testing Terms

Due to the unique design of the Blind Bolt there are a number of different fixing combinations possible. Although the tensile strength of the Blind Bolt remains constant, the shear strength of the Blind Bolt can vary depending on the thickness of the material being clamped. These variations are explained below.

Use the menu to see an explanation of the testing criteria found on our technical data sheets. However, if there is anything that you are unsure about please feel free to contact us on the number below or click here to send us an e-mail.

What is Tensile Strength

This is the ultimate pullout force required for the bolt to fail when under a tensile load.

What is Shear Strength Over Slot

This is the ultimate force required for the bolt to fail when the shear plane, produced by the two materials being clamped, falls over the slotted portion of the Blind Bolt near the anchor when the bolt has been installed in the correct vertical alignment.

what is Shear Strength Over Thread

This is the ultimate force required for the bolt to fail when the shear plane, produced by the two materials being clamped, falls over the threaded portion of the bolt.

Blind Bolt

Fixing Data Explained

Blind Bolt Technical Data - fixing terms

Due to the unique properties of the Blind Bolt there are certain operation criteria that must be met to ensure its successful application. These dimensions are outlined below, please use the menu to the left to isolate each dimension and view a brief description.

However, if there is anything that you are unsure about please feel free to contact us on the number below or click here to send us an e-mail.

What is Minimum Fixing Thickness

This is the minimum distance that the bolt is able to clamp.

This is calculated from the overall thickness of all materials being clamped.

What is Maximum Fixing Thickness

This is the maximum distance that the bolt is able to clamp.

This is calculated from the overall thickness of all materials being clamped.

what is Anchor Clearance

This is the minimum distance required for the successful deployment of the Blind Bolt's anchor.

Careful attention must be payed to this criteria when fixing into Steel Hollow Sections to prevent the anchor catching on the section wall.

what is Depth Clearance

Depth Clearance is the minimum distance required within a cavity to allow the Blind Bolt's anchor to deploy.

Careful attention must be payed to this criteria when fixing into Steel Hollow Sections to prevent the bolt reaching the opposite section wall before the anchor has deployed.

what is Hole Centers

This is the minimum distance required between bolts when installing multiple Blind Bolt's.

Blind Bolt

Fitting Instructions
Installations & Removal Videos

The following videos visually represent both the detailed installation and removal of the Blind Bolt.

Blind Bolt Downward Installation

Blind Bolt Downward Installation

Blind Bolt Horizontal Installation

Blind Bolt Horizontal Installation Video

Blind Bolt Vertical Removal

Blind Bolt Vertical Removal Video

Blind Bolt Horizontal Removal

Removal Installation Video

Blind Bolt Fitting Instructions (PDF Download)

Blind Bolt

SCI Report