EFS has recently completed the production of two oversized screws, a hex head UNI 5740 and a socket head UNI 5931, now ready for shipment.
These fasteners are intended for cement mill equipment and structural joints in heavy-duty mechanical applications.
In advanced mechanical engineering, certain projects require non-standard screws capable of withstanding extreme loads and harsh conditions. Let’s take a closer look.
Oversized Hex Head Screw UNI 5740
The first item is a hex head screw UNI 5740, Class 8.8, measuring 48 x 3 x 180 mm.
It has been heat-treated and black oxide coated, and its technical complexity lies in the combination of a large diameter and a fine thread pitch—a challenge when performing heat treatment, as the thread can deform if not properly handled.
This screw will be used in structural connections between thick steel plates, bases, and metal frameworks.
Oversized Socket Head Screw UNI 5931
The second item is a socket head screw UNI 5931, Class 12.9, measuring 30 x 600 mm, also black oxide coated.
Its non-standard length makes the process complex: during heat treatment, screws of this type may warp if not manufactured with the right expertise.
Furthermore, very few certified suppliers can hot-forge screws of this hardness and geometry.
This screw is intended for crushing systems in cement plants, where mechanical strength and dimensional repeatability are critical.
Technical Challenges Successfully Overcome
Both the UNI 5740 and UNI 5931 oversized screws were manufactured to customer specification, internally tested, and are now ready for delivery.
This is yet another example of EFS’s ability to manage non-standard special fasteners, carefully overseeing every stage: from selecting qualified manufacturers to final quality checks.
Discover more about our screws, ready to be paired with standard or custom nuts, on our website.
Watch the reel:
