yhdistelmäruuvit

Yhdistelmäruuvit, also known as combination screws or twin-lead screws, are specialized fasteners designed to join different materials or achieve specific thread functionalities within a single screw. Their defining characteristic is the presence of two distinct thread types on the same shank.

One common configuration features a coarse wood thread on one end and a fine machine thread on the other. This allows for a secure grip in softer materials like wood or plastic with the wood thread, while the machine thread provides a strong connection to a pre-tapped hole in a metal component. This type of yhdistelmäruuvi is frequently used in furniture assembly, cabinet making, and general construction where wood and metal are joined.

Another variation might involve two different diameters of machine threads, or a machine thread combined with a self-tapping thread. The purpose of these combinations varies. For instance, a screw with two machine threads of different pitches could be used to achieve a controlled withdrawal or a specific load-bearing characteristic. Screws with a self-tapping thread at the tip are useful when inserting into sheet metal or other materials where a pre-drilled pilot hole might not be ideal, allowing the screw to create its own mating threads.

The use of yhdistelmäruuvit simplifies assembly processes by eliminating the need for separate nuts or inserts in certain applications. They offer a convenient and efficient solution for joining dissimilar materials or for achieving specialized fastening requirements.