Very filetee

When ordering a threaded rod, it is essential to specify:

  • The steel quality class (4.8, 6.8, 8.8 etc…).

  • The length (1, 2 or 3 meters).

  • Coating (raw steel, zinc-plated steel, dichromated steel, stainless steel, etc.).

  • Not.

  • Thread quality class.

Thread quality = safety:

All the threaded rods delivered by Screw-express have a thread angle of 60° ±2°.

 

We inform you that some suppliers market non-compliant threaded rods (thread angle of 37°, 43°, 52°, etc.)instead of 60° for an ISO metric thread with triangular thread 6G (raw)/ 6H (galvanized) according to NFE 25-136.

 

The angle of the threads on the non-conforming rods allows a saving of material which is compensated by thinner and therefore more fragile threads, hence a strong impact on the tearing resistance of the threads.

 

Here are the results following tests carried out in a laboratory. These results are without comment.

 

Tear-out force divided by 2: 33.4 kN on compliant rod (60° thread angle)

17.4 kN on non-conforming rod (37° thread angle)

Stress resistance: we see that the non-compliant rod has no resistance to stress and that the threads tear off immediately after only 2 mm of displacement, whereas the conforming rod has resistance to linear load over approximately 4mm and a total displacement of over 5.6mm before the threads strip. 

We deem it necessary to inform you that non-compliant rods are marketed at necessarily competitive costs.

Comparison of 2 threaded rods on a profile projector