Thread standards abound - from widely used standard threads to obscure special cases. However, in order to find your way around in your daily work as a do-it-yourselfer or craftsman, a few thread standards will suffice as a point of reference.

Since this type of thread is used very frequently in Europe, you have probably already worked with it yourself. The thread standard for the metric standard thread is a fastening thread that is used, for example, for screws and nuts. It has a flank angle of 60° and is identified by the abbreviation M and the nominal diameter. Since this is a metric thread standard, all dimensions are given in mm.

This type of thread is a variant of the ISO metric standard thread with a smaller pitch and thread depth. The small pitch in the MF metric fine pitch thread makes it possible to determine the position of a screw very precisely. The thread standard is therefore often used for adjusting screws. In addition, fine threads with this standard have good self-locking properties and, thanks to their shallow depth, can be used even where space is limited. The abbreviation MF is used for the thread designation.

The trapezoidal thread is also a metric thread standard, accordingly all dimensions are given in mm. The flank angle here is only 30°. A striking feature of this thread is the profile, which is not pointed, but rather has the shape of an isosceles trapezoid. This makes the trapezoidal thread well suited as a movement thread and in this capacity it can be found in lathes or screw presses, among other things.

At this point we enter the field of American thread types. With a flank angle of 60°, the American coarse thread is similar to the metric ISO thread and is also roughly the equivalent of this thread standard in the USA in terms of function and distribution. It is important to note that all dimensions are in inches. Also, in the case of American threads, the pitch is given by the number of threads in inches. A small but important detail that can be confusing at first glance.

As with metric threads, there is a fine thread to the coarse thread in American threads. The flank angle of the American fine thread is 60° and here, too, all specifications must be made in inches. Like the UNC thread standard, the UNF thread standard is also widespread worldwide and is used not only in the USA but also in Japan and Australia, among other countries.

The UNS thread standard is a special standard for threads. This standard also has a flank angle of 60°, but differs from the other American threads by special diameters, pitches and screw-in lengths. This American thread with special pitch can be found, for example, in microphone stands.

While the NPT thread is also one of the American thread standards, it is not part of the Unified Thread Standard (UTS). Rather, it is part of a group of standards for pipe threads. The American pipe thread is tapered, non-sealing, and has a flank angle of 60°.

Let's continue with the British threads. The British coarse thread is the standardized standard thread in the UK, similar to the metric thread standard in mainland Europe. The dimensions are given in inches. Be careful with the flank angle, because it is only 55° here. The thread abbreviation for this thread standard is composed of the abbreviation BSW and the nominal diameter in inches.

The British thread standards also know the fine thread to the BSW thread. The British Standard Fine Thread (BSF) has a flank angle of 55°. The British fine thread used to be an important part of the glorious British automotive industry, but has since lost importance. You can recognize this thread by the thread designation BSF followed by the diameter in inches.