Yksikierre

Yksikierre is a Finnish term that translates to "single thread" or "one turn." In technical contexts, it most commonly refers to a single-start thread, which is a type of screw thread where there is only one helical ridge that engages with a mating thread. This is in contrast to multi-start threads, which have two or more parallel helical ridges.

Single-start threads are the most common type of screw thread and are used in a vast array of applications, from simple fasteners like bolts and screws to more complex mechanisms such as lead screws and jacks. Their prevalence is due to their simplicity in manufacturing and their ability to create a secure, strong connection. When a single-start screw is turned, it advances axially by a distance equal to its pitch in one complete revolution. The pitch of a single-start thread is the distance between adjacent threads, measured parallel to the axis of the screw.

In contrast, a double-start thread would have two intertwined helical ridges. When a double-start screw is turned one revolution, it advances axially by twice its pitch. This allows for faster linear motion for the same rotational speed, but it typically results in a less strong connection and can be more complex to manufacture. Therefore, the choice between single-start and multi-start threads depends on the specific application requirements, balancing factors like speed of engagement, load-bearing capacity, and manufacturing complexity. The term yksikierre, by its very nature, signifies this fundamental and most common form of screw thread.