the standard

Blind Bolt

The versatility of the Blind Bolt means that our clients are constantly devising different applications and new uses.

The Blind Bolt Fixings

We reflect this innovation by manufacturing an increasing number of new sizes, all designed to save time and money. Blind Bolts have rendered the preceding generation of blind fixings more or less obsolete.

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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 Technical Data - fixing 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 Zinc Flake 1000Hr SSP - Property Class 10.9

Product Code Bolt Size Box
Qty
Hole
Diameter
Fixing
Thickness
Min Max
Anchor
Clearance
Depth
Clearance
Minimum
Hole Centers
BB0850DTASM M8x50 50 9 9 24 19 25 20
BB1060DTASM M10x60 40 11 10 30 23 30 20
BB1095DTASM M10x95 20 11 25 65 23 30 20
BB10130DTASM M10x130 20 11 55 100 23 30 20
BB1270DTASM M12x70 20 13 12 35 26 35 25
BB12120DTASM M12x120 25 13 30 85 26 35 25
BB12180DTASM M12x180 20 13 80 140 26 35 25
GBB1690DTASM M16x90* 20 17 13 43 36 43 35
GBB16130DTASM M16x130* 15 17 40 75 36 43 35
GBB16180DTASM M16x180* 10 17 55 125 36 43 35
GBB20110DTASM M20x110* 10 22 21 56 44 56 48
GBB20140DTASM M20x140* 8 22 21 86 44 56 48
GBB20180DTASM M20x180* 10 22 80 120 44 56 48
GBB20250DTASM M20x250* 10 22 130 185 44 56 48
GBB24130DTASM M24x130* 5 26 21 66 53 64 60
GBB30140DTASM M30x140* 5 32 27 60 65 72 75
* 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.

Blind Bolt Design Capacities NZS 3404:1997 or AS 4100:1998

Diameter Tension Capacity
Φ'Ntf (kN)
Shear Capacity
Over Thread
Φ'Vf (thread) (kN)
Shear Capacity
Over Slot
Φ'Vf (slot) (kN)
Recommended
Tightening
Torque (Nm)
M8 6.9 14.6 11.1 15
M10 12.9 23.2 19.0 24
M12 18.8 33.7 26.3 30
M16 40.1 62.7 51.5 50
M20 57.8 97.9 76.1 65
M24 82.3 141.0 105.4 75
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

The bearing capacity of the ply should be calculated in accordance with the design Standard, based on the nominal diameter df of the bolt. No reduction for the slot is necessary. Bolts subject to combined shear and tension should be verified in accordance with the design Standard, using the values of Φ'Vf (slot) and Φ'Ntf from the table above. The above design values were prepared by SCI, UK, following a program of tests. Design values verified by HERA, NZ are shown below

Diameter Tension Capacity

Φ'Ntf (kN)

Shear Capacity
Over Slot
Φ'Vf (slot) (kN)
M10 12.0 20.6
M20 63.7 122.5
M24 86.7 202.6
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 M8x50 50 9 9 24 19 25 20
BB1060A4ASM M10x60 40 11 10 30 23 30 20
BB1290A4ASM M12x90 20 13 12 55 26 35 25
GBB16100A4ASM* M16x100 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)
 
M8 5.3 10.3 6.5 20.7 24.8 15
M10 12.7 16.2 11.1 27.6 33.0 22
M12 21.4 23.6 15.4 32.2 38.5 28
M16 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

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)
 
M8 5.3 12.3 7.8 65.6 75.2 15
M10 12.7 19.5 13.3 82.0 94.0 22
M12 22.0 28.3 18.4 98.4 112.8 28
M16 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 Technical Data - fixing terms

Blind Bolts are incredibly versatile and can be used in a wide number of fixing combinations. This variety means that the measured strength of the Blind Bolt in question can also vary. This where the testing data comes in.

Whilst the tensile strength of the Blind Bolt is constant no matter how it is used, the shear strength varies depending upon the thickness of the materials being fixed together.

A summary of the factors involved in these variations is set out below, and for a more detailed account, you can access our technical data sheets via the menu at the top of the page.

If there are any questions remaining about the testing data, fell free to contact us with an enquiry via the contact details at the bottom of the page, or by clicking here to send an email.

Blind Bolt

Fixing Data Explained

Blind Bolt Technical Data - fixing terms

Utilising the unique and innovative Blind Bolt system effectively means being fully aware of the way in which the dimensions of the bolt are measured and classified.

These dimensions then play a vital role in meeting the criteria for successful application.

The details of these measurements are set out below and the menu above offers pictorial representations.

If you have any more enquiries regarding the fixing terms for our blind bolts, contact us using the details given at the bottom of the page of by clicking here to send an email.

Blind Bolt

How to Fit a Blind Bolt

The best fastener is one which stays in place for a long period of time without requiring a lot of maintenance, enabling projects to be completed quickly and simply. Blind bolts offer these properties which is why they’ve become incredibly popular over just a short period.

Fitting a blind bolt isn’t just a question of twisting it into a hole, however. In order to make sure that the bolt is fitted correctly the following factors have to be considered:

  • The size of the hole
  • The length of the joint
  • The angle
  • The tools needed for the job.

If all of these factors are taken into account and the bolt fitted correctly you can be certain it won’t fail over time.

1. The Size of the Hole

Two factors are directly determined by the size of the hole, and these are the length of the grip and the length of the blind bolt itself. These are two different measurements impacting on the solidity of the joint, so both have to be taken into account. In simple terms, if a bolt is too big or too small for the hole in question it could work loose. In most cases, a supplier will provide a guide which can be used to gauge the correct length, or you could purchase grip gauges. Using a meter means that you can check which sizes are suitable after drilling a hole.

2. Choose the Best Type of Blind Bolt

The many variations of blind bolt on offer are a huge benefit, but they can also be a problem. The problem arises because it can be tricky to decide exactly which bolt is the right bolt for the job in hand. Blind Bolts ranging from hollow wall to heavy duty can be purchased online and in stores, so it’s vital to know exactly what you need before making a purchase. Success means matching the right bolt to each project. The following are examples of the properties of two bolts:

M8 diameter – tension and shear capacity of 9.8pt and 14.6ps respectively
M30 diameter – tension and shear capacity of 174.5pt and 224.0ps respectively
This means that if you’re doing a job which involves high levels of pressure the M30 would be the best choice.

3. Proper Equipment

It’s possible to install a blind bolt with just a screwdriver and lots of effort, but no matter how hard you work the joint won’t be completely flush, and this will impact on the tensile and shear strength of that bolt. To do the job properly you have to invest in hydraulic and power tools which can set the bolt in position quickly and easily. Tools of this kind won’t just provide maximum strength and efficiency, they will also provide a more professional finish to the job. If hand held tools are utilised, make sure that they apply sufficient power to the bolts.

4. If the Bolt Isn’t Fitted Correctly

The seal created by the bolt should be completely flush, and if it isn’t the bolt needs to be removed and re-fitted. In some cases it will be enough to simply loosen the bolt and push it further into the hole, creating a tighter grip. If this doesn’t work it might be worth reconsidering the type of bolt being used, as this can impact your installation. Our installation and removal videos contain more detailed information.

If utilised correctly, Blind Bolts are extremely effective while still being affordable.

5. Bolted Shut

Blind bolts offer a flexible solution, with the range of sizes on offer increasing to meet client requirements. In addition, the versatility of the bolts means that we’re always coming up with new ways in which they can be used to save clients time and money.

Interested in finding out more about our blind bolt fixings and blind bolt installation? Get in touch today and speak to a member of the Blind Bolt team today on 0800 42 52 56 or send us an email on enquiries@blindbolt.com.nz. We look forward to hearing from you.

Blind Bolt

Fitting Instructions
Installations & Removal Videos

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

Blind Bolt Horizontal Installation & Removal

Blind Bolt Horizontal Installation Video

Blind Bolt
Horizontal Installation

Blind Bolt Horizontal Installation Video

Blind Bolt
Horizontal Removal

Removal Installation Video

Blind Bolt Downward Installation

Blind Bolt Downward Installation

Blind Bolt Vertical Removal

Blind Bolt Vertical Removal Video

Blind Bolt Fitting Instructions (PDF Download)

Blind Bolt

SCI Report