GROWER TENKEEP®’s perfect grip 28 March 2019

With its technical know-how, use of simulation software, and numerous laboratory tests, Growermetal’s R&D department has developed GROWER TENKEEP® flat safety washers, which will be launched on the market at Fastener Fair Stuttgart.

When compared to other safety washers on the market, GROWER TENKEEP® safety washers have knurls with a different geometry on each side of the two surfaces – specially designed to ensure maximum performance against unscrewing of the bolted joints even in the presence of extreme vibrations and dynamic loads.

In fact, thanks to the different geometry of its surfaces, the GROWER TENKEEP safety washer becomes immediately solid to the bearing surface when the bolted joint is tightened, while the screw continues to rotate. In this way the friction conditions are defined and uniform and therefore the tightening torque to be applied, in order to reach the required preload, is independent from the material and the mechanical characteristics of the supporting surface. There is no damage of the supporting surface during its application, even on galvanised or painted surfaces.

Growermetal Srl says its GROWER TENKEEP safety washers guarantee the perfect grip of the bolted joint on all metallic materials with variable hardness range between 100HV and 350HV. The main advantages also include excellent locking performance in the presence of vibrations and dynamic loads, precise correspondence between tightening torque and screw preload, regardless of the material of the supporting surface, and minimal space requirement compared to the type of nuts and bolts used. There is also no geometric interference between the washer’s hole and the underhead radius of all the screws according to ISO and DIN standards. After assembly, the washer will always remain inside the screw head.

For use with all types of bolts up to Class 12.9, the GROWER TENKEEP washer series is also suitable for applications with embedded holes and has a standard surface coating with very high resistance to corrosion. The series is also assembly friendly due to the presence of an internal chamfer indicator and reusable performance.

Finally, with functionality regardless of the presence or absence of lubricant, and with excellent price/performance ratio, the GROWER TENKEEP safety washer is produced in three standard series: Medium series from M3 up to M30 (ideal for hexagonal bolts), large series from M5 up to M20 (ideal for flanged head bolts, soft material support surfaces and slotted holes), and lastly the cylindrical series from M4 up to M30 (ideal for cylindrical head bolts).

Deputy Editor

Claire Aldridge Deputy Editor t: +44 (0) 1727 814 450


Having joined the magazine in 2012, Claire developed her knowledge of the industry through the numerous company visits, exhibitions and conferences she attended both in the UK and abroad.

Claire prides herself on keeping readers well informed and up to date with the latest industry news.