BoxBolt® FAQs

Yes. Hold the collar and un-screw the bolt. The collar can now be separated from the sleeve and the outer ply can be removed. The sleeve can be pried out if required or simply knocked through to the inside of the connection.

A clearance hole for the outside sleeve of the BoxBolt is required. A common mistake is to drill a clearance hole for the core bolt only but the hole must be larger to allow for the sleeve.

You will need to know the diameter of the BoxBolt that you wish to use by referring to our technical tables and reviewing the loading capacities. Once you have determined the diameter of BoxBolt, you will then need the total thickness of steel you are connecting to. You can then use the technical tables by looking at dimension X to decide which is the most appropriate length for your application (1, 2 or 3).

The BoxBolt is available in three lengths per diameter. The length is determined by comparing the total thickness of your steel to be connected to dimension X in the technical table. The sizes overlap between 1 and 2 and also between 2 and 3 so it might be that you can use two lengths for your application. The most economical length will always be the shortest but you may wish to commonize on one length for convenience.

The BoxBolt uses an expansion mechanism which is only placed in tension enough when the correct tightening torque is applied. As this is a blind connection, it is essential to tighten the BoxBolt to this torque to ensure full engagement. This is true for both tensile and shear conditions.

The BoxBolt is often used with slotted brackets to provide adjustment on site. The hole in the primary material where the BoxBolt expands in must always be a circular hole drilled to our recommendations, however, the external hole that fits to the underside of the collar can be slotted as long as the width of the slot is not wider than the hole diameter. If the load is in the direction of the slot, then you will need to reach out for additional advice.

The BoxBolt features a clever interlocking mechanism between the collar and the sleeve to stop rotation while tightening. This allows for a small amount of separation once the expansion sleeve locates on the inside of the connection. This separation allows the sleeve and collar to act separately like a nut and bolt. The pre-load in the bolt is transferred to the area where the expanding sleeve makes contact with the inside of the blind hole.

The engagement of the expansion mechanism of the BoxBolt allows it to be used on rectangular, square or round tube sections. The sleeve expands on the inside of the hole evenly. A standard nut and bolt cannot be used on a round tube since a flat surface is required.

Geomet finish provides a combination of an aesthetically pleasing finish with excellent corrosion resistance. The coating is very smooth which is perfect for fasteners since it has a very low co-efficient of friction. A minimum amount of clamping force is lost through friction between the bolt and threaded cone due to its low co-efficient of friction.

Yes. We can produce BoxBolt to suit most blind steel connections. This may include modifying the head for an aesthetic reason or creating a spacer to make it longer. We will even consider different diameters and finishes if there is the volume to justify it.

Yes. We can produce BoxBolt to suit most blind steel connections. This may include modifying the head for an aesthetic reason or creating a spacer to make it longer. We will even consider different diameters and finishes if there is the volume to justify it.

A minimum spacing is required between two bolts to make sure they do not clash when they are expanded. This dimension is given as dimension A in our technical tables. When using a BoxBolt close to corners of tube steel it is important to check the clearance to the inside, dimension B plus the thickness of the tube steel will give the minimum dimension to the center of the hole.

Our technical table provides a dimension for the thickness of the shoulder and the length of the bolt used in each BoxBolt which then allows a calculation to be made to check that no interference occurs.