High-tech Gearbox Repairs Return Units that are Better than Before

Renold Gears' gearbox-repair service was put to the test just recently when it won the contract from steel maker Corus to refurbish the massive dog-bar gearboxes at its Teesside Beam Mill. The gearboxes are amongst the biggest Renold has ever repaired, standing over five feet high and weighing in at around ten tons each. They are over 40 years old and now require re-engineering to a very high standard. The gearboxes were originally manufactured in 1964 by Crofts Engineers, of Bradford, a company that was acquired by Renold just three years later in 1967. The original blueprints were found in the company's archives and so components for the gearboxes could be manufactured to their original specifications, but modified for enhanced performance. Renold's repair team improved the original specification in several ways so that the repaired unit was better than when it was new. The team redesigned and upgraded the material of the output shaft and fitted an internal pumping system to feed lubrication directly to the gears and bearings. The case was also ultrasonically tested for leaks prior to reassembly with the new gears, shafts, bearings and the new pumping system.