Probably, many of you faced problem of the choice of suitable fasteners, especially self-tapping screws. If desired or need to carry out personally repair and construction jobs, many remain in difficult situation before good selection in hardware store when choosing suitable self-tapping screws.
Knowledge of elementary rules of selection of self-tapping screws, helps to save time which leaves on consultation at sellers and on comparison of various self-tapping screws with each other.
When choosing first of all look at type of material which needs to be fixed by means of self-tapping screws. It is easy to distinguish self-tapping screws on tree and simply, at them tips are sharp, and thread pitch wide. And here self-tapping screws on metal have many options, but their main quality, this production from high carbon steel, thread with small step and corrosion-resistant coating.
Self-tapping screws happen from brass and carbon steel. The lowest at cost are the self-tapping screws executed from carbon steel with protecting cover. They are suitable for fastening among themselves of wooden and metal parts, when there is no need for the high accuracy of connection. Also they are separated by the form protecting cover. Self-tapping screws with the oxidized covering of black color are used in rooms with average humidity level. Galvanized self-tapping screws of silvery color are used in and outside of the room. And zinced yellow color, are applied in the decorative purposes.
Self-tapping screws also differ on thread frequency. If thread dense - that the self-tapping screw is intended for twisting in solid metal.
Also when choosing the self-tapping screw it is necessary to pay attention to head form. If it hemispherical, then is suitable almost for all connections, providing strong fastening at the expense of the latitude of the square with the pressed head. There is head to washer hemispherical too, such self-tapping screws reliably hold connections from sheet materials. And hemispherical about big press washer allows to press densely even soft materials.
When choosing the self-tapping screw it is necessary to pay attention to designation of the sizes. For example, if there digits 5 and 30, then the first digit 5 specifies the outside diameter of thread in millimeters, and the second digit, it is self-tapping screw length. We hope that these recommendations will help you when choosing self-tapping screws.