Referred to as screw to an element or cylindrical with a head mechanical operator, usually metal, although they can be of wood or plastic, used in the temporary fixation of some pieces with each other, which is fitted with a cane threaded with triangular thread, which by a twisting force exerted on his head with a suitable spanner or a screwdriver, you can insert into a threaded tailored or cross pieces and attached to a tuerca.1
