Fix master Square neck with round pan head

Used in wood construction, especially in carpentry, in prefabricated house construction and vehicle construction (e.g. in load supports in trucks), in boat construction, in building structures for fairs, in manufacturing frameworks, heavy temporary transport racks or machine crates, as well as in manufacturing transportation crates for marine transfers. For connecting wooden parts or wooden and metal parts. Square neck sinks into the wood. The diameter of the hole depends on the dimensions of the thread. When wood is attached to wood, a large washer (e.g. a special washer for wooden structures) must be placed under the nut.