BCT®: Beyond rivet nuts 04 April 2024

Founded in Italy in 2001 by German national Herbert Schruff, BBA Srl is a manufacturer and designer of rivet nuts and rivet nut studs, with a clear focus on rivet nut innovations, such as its patented BCT® (Bulge Control Technology) rivet nut design.

Standard rivet nuts are a tried and tested means of providing a riveted (permanent) threaded fixing point to thin sheet metals. However, as application requirements increasingly evolve, standard rivet nuts are not suitable options. Where this is the case, BBA’s BCT® takes rivet nuts beyond known capabilities and achieves new performance heights.   

BCT® is a revolutionary technology comprising of weakening points positioned on the shank of a rivet nut or rivet nut stud. These weakening points precisely predetermine where the bulge will start forming, independent of the application material. The bulge always forms from behind the sheet, pulling it up onto the sheet (clamping it) and therefore avoiding radial expansion on the side walls of the hole. These features mean that rivet nuts and rivet nut studs using BCT® can offer new and exciting application solutions. 

BCT® Controlled is a range of rivet nuts and rivet nut studs for use in composite and plastic materials, where traditional rivet nuts risk deforming or cracking the application material. As BCT® Controlled places no radial force on the walls of the hole, the rivet nut may be installed very near to the edge of the application without risk of cracking the material. As the bulge formation is independent of the application material, BCT® Controlled is also suitable for use in applications where conditions mean that irregular or oversized holes may be present.

BCT® Ultra is a range that achieves the maximum tightening torque loads of Class 12.9 bolts. As the entire product is made from a higher tensile steel of 600MPa (versus 330 MPa for standard rivet nuts) not only the thread is stronger, but the entire product is stronger, thus the bulge is able to maintain the pretension of the mating bolt and offer a very low and consistent torque angle. The BCT® Ultra range is available in rivet nut and rivet nut stud options and offers an alternative to welded nuts and welded studs, avoiding the issues associated with the welding process and is often used as a repair solution for failed welded products. Furthermore, this range is routinely used as an electrical grounding solution and particularly for use on non-metal sheet applications where welding is not possible.

Also available, the BCT® Micro range is fundamentally a BCT® Ultra but physically smaller with less threads and therefore can be installed into application spaces too small for standard rivet nuts to fit into. The high strength nature of BCT® Micro means that despite its smaller size, the product still yields thread strength compatible for use with Class 8.8 bolts and their recommended tightening torques, thereby providing load bearing threads in restricted spaces.

Another innovation is the BCT® Nail Nut, specifically designed where high torque to turn performance is required in application materials that are softer than steel. This includes most grades of aluminium, plastics and composite materials. To increase torque performance in such materials, hexagon holes are used in conjunction with hexagon bodied rivet nuts. In such cases, the failure mode is generally the sheet material that often deforms around the rivet nut body at relatively low torque levels. With the BCT® Nail Nut, 4 teeth protruding from under the head of the rivet nut (or stud) are pressed into the surface of the soft sheet material during the installation process. The teeth penetrate into the softer sheet material creating a locking feature that provides outstanding anti-torque to turn resistance. To maximise anti-torque to turn rotation, BCT® Nail Nut can be deployed together with a hexagon or knurled body on the rivet nut too.

Finally, BCT® Floating is an innovative way to address alignment issues and provide gap compensation. The rivet nut is only partially installed into a slotted hole. As there is no radial expansion in the hole, BCT® Floating is then free to travel the length of the slot and cannot ‘fall out’ as it is retained by the partially formed bulge. Later, when the bolt of the mating component is presented to the rivet nut, the bolt can be used to position the BCT® Floating so that it is perpendicular to the bolt. As the bolt is then torqued further, it completes the installation of the BCT® Floating and then tightens the component to the rivet nut to the desired application tightening torque.

Given that all of BBA’s products are manufactured in Italy, whether a standard rivet nut or an enhanced BCT® rivet nut is required, the customer is assured that by choosing BBA as a partner, their supply chain is as secure as possible. Coupled with the fact that BBA remains 100% family owned, the company is able to offer its customers branded products that are backed by the quality, performance, reliability and dependability you would expect from a leading European manufacturer.  

Claire Aldridge Deputy Editor t: +44 (0) 1727 743 889

Having spent a decade in the fastener industry experiencing every facet – from steel mills, fastener manufacturers, wholesalers, distributors, as well as machinery builders and plating + coating companies, Claire has developed an in-depth knowledge of all things fasteners.

Alongside visiting numerous companies, exhibitions and conferences around the world, Claire has also interviewed high profile figures – focusing on key topics impacting the sector and making sure readers stay up to date with the latest developments within the industry.