Glossary Fine pitch thread

A screw with a fine pitch thread – also known as an ISO metric fine pitch thread – has a smaller pitch than a screw with a standard thread. This means that the distance between two thread stages during one revolution is smaller and the threads are closer together

This is achieved by a narrower thread profile that is cut less deeply than the profile of a screw with a standard thread.

A fine pitch thread is more complex to produce than a standard thread, but has advantages for some applications.

The advantages of fine threads lie in their higher precision and better fit. As the threads are closer together, they can be interlocked more closely, which enables greater rigidity and higher accuracy in the transmission of forces and torques. This is particularly advantageous for small threads, as the connection force is increased by the tight fit.

Another advantage of fine threads is their higher load-bearing capacity. Due to the larger contact surface, the bolt and nut are more closely interlocked. As a result, they can transmit higher forces than conventional threads. Fine threads build up more pressure with the same tightening torque. This is particularly important in applications where high loads occur, such as in the aerospace industry.

Fine threads can also provide a better seal than conventional threads. As the threads are closer together, it is more difficult for liquids or gases to pass between them. This is particularly important in applications where leaks must be avoided, such as in medical technology or the gas industry.

Finally, the narrower threads also offer advantages. This allows the adjusting screws of measuring devices to be set more precisely. In addition, fine threads have a higher self-locking effect. Screw connections cannot come loose so easily – for example due to vibrations – and screw locking is not always necessary.

And finally, fine threads for special applications can save valuable space, as the thread is shorter with the same number of turns.

One disadvantage of fine threads is that they are not cut as deeply as standard threads. They can therefore escape more easily. They are also generally more difficult to produce than conventional threads and require special tools and machines.

Screws or nuts with a fine pitch thread can be recognized by an addition to the dimension. Where only the diameter is specified for screws with standard threads, for example M 10, this information is supplemented by the pitch value for screws with fine threads. M 10 x 1.5 then stands for a pitch of 1.5, for example.

In many cases, screws with fine threads are custom-made products that are produced by the screw manufacturer as special screws or special screws according to drawings.

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