Steel-to-steel fixing goes nut-free

The new TDBL nonut® self-threading screw from SFS, one of the world’s leading manufacturers of high performance fasteners, enables a secure connection of pre-drilled supporting steel structures without any nuts or washers.

Compared to the standard method of using nuts, bolts and washers, the precision-engineered TDBL nonuts® fastener is a quicker, more efficient and secure way of fixing supporting steel structures of various thickness and hardness together subject to static load. The installer only needs one component instead of three and one hand tool. Installation is one-handed and requires access from just one side. Thanks to the innovative design of the TDBL nonut® with its thread-free zone and additional serration under the head, the risk of over-driving in thin steel is prevented and the connection remains robust. European-manufactured to a high quality, the plated carbon steel, case hardened TDBL nonut® is available in eight variants according to length, diameter and clamping length with a hexagon head.

The quality and effectiveness of the TDBL nonut® has been well established in Germany, as it is the only solution of its kind with the German national technical approval (“Allgemeine bauaufsichtliche Zulassung”). However, it has been widely used across mainland Europe and the rest of the world in diverse fields of application such as steel beams, stairways, railings, pylons, water tanks, grain silos, fall protection systems, rack constructions and solar parks. A current case study is Panama airport where 28,000 TDBL nonuts® are being used in the project’s construction. And nearer to SFS UK’s headquarters in Leeds, 70,000 TDBL nonuts® have been used in the three-storey structural mezzanine system of a large 516,750 sq.ft. distribution centre near Ferrybridge. The TDBL nonut® has been mainly used in the columns and beam-to-column connections. The product’s unique design has enabled other design changes to be made to the structure of the mezzanine that have complemented structural performance and installation benefits.

Andy Stolworthy, Director of Product and Market Development, at SFS UK says:

“The traditional method of fixing steel structures together by using bolts with nuts and washers represents an unnecessarily awkward and time-consuming way of doing things. We’ve worked to overcome this by developing the TDBL nonut®, a technically superior fastener in one piece rather than three. It’s a risk-free alternative that is guaranteed to make steel structure assembly faster, and the customers get the peace of mind of knowing that it’s a product from a global-market leader renowned for quality.”

The TDBL nonut®, like all products from SFS, is backed with expert technical support that has been at the core of the company’s success in serving the construction and manufacturing industries. Operating from its UK HQ in Leeds, the company is part of the Swiss-based SFS Group which has annual sales in excess of £1.1bn and a history dating back to the 1920s serving customers in the construction, automotive, electronics, industrial and medical products markets.

Find out more about the TDBL nonut® and SFS at