“We were able to use closer tolerances because of the accuracy of tube laser cutting, compared with traditional punching,” he explained. “If you look at the European fabrication standards for the bolt sizes we are using – M12, M16, M20 – they recommend a tolerance of two millimetres, and three on bigger bolts. We have reduced them by a millimetre, which gives a much better fit and it’s less sloppy. That makes the constructions more resilient, which means they will last longer.” The clearance for a 16mm bolt is usually 18mm; working with SSC Laser, we were able to get it down to just 17mm, which was reduced even further after galvanising. Because the tolerances were so tight – and repeated, time after time on all the components for all 103 units – the team assembling the towers didn’t have to worry about realignment of accumulated minor deviations, facilitated by over-generous tolerances. Nor did the ground crews; the towers were bolted together, the helicopter carried them over, the team installed them and the chopper was immediately off to get the next one.

“The tight tolerances saved time and enabled fast turnaround, which saved money with the helicopter – which was expensive!” said Brannan. The experience on the BIFoR FACE project has built a relationship that has led to work on additional projects. While the tower business is not generally time-critical, there are always exceptions and SSC has been able to meet our needs. Above all, they helped Brannan’s company get the job done, quickly and efficiently.