All about metal screws

Metal - This is one of the most popular and frequently used materials today. It has found wide application not only in the metallurgical industry and various manufacturing enterprises, but also in everyday life. Many different designs and products are made from it. And in order to work with metal, you need a lot of special tools and consumables.

One of these is the screw. It is about screws for metal that will be discussed in this article - about their features, types and selection criteria.

Screws are fasteners and are considered a type of self-tapping screw. The screw design is quite simple. This is a rod that consists of two sections: one is straight, and a thread is cut along the entire length of the other. The head of the product is semicircular, and the end is very sharp.

All metal screws are characterized by the following parameters:

• thread diameter - from 1.6 to 10 mm;
• internal thread diameter - from 1.1 to 7 mm;
• thread pitch - from 0.8 to 4.5 mm;
• straight slot width - from 0.4 to 2.5 mm;
• the size of the cross slot is 1-4 mm.

Screws are made according to norms and rules, which are provided for in state documents, namely: GOST 1144-80, GOST 1145-80, GOST 11473-75.

Screws for metal used in the assembly of metal structures. That is why they should be:

• durable;
• reliable;
• not to be afraid of the impact of various negative factors;
• resistant to wear and tear;
• simple and easy to install.

It is very important that such a product has a long service life. To achieve this technical parameter, only high-quality materials are used in the production of fasteners - carbon and stainless steel, brass... Already finished products cover with a special compound.

The range of screws for metal, which is currently presented on the fasteners market, is more than large and varied. There are many types of products:

• sharp black - length from 19 to 152 mm, outer diameter from 3.5 to 4.8 mm;
• with a drill or, as it is also called, self-drilling - product length from 9.5 to 75 mm, outer diameter from 3.5 to 4.2 mm;
• with a press washer - the fastening element is characterized by a length from 13 to 76 mm, an outer diameter from 3.5 to 4.2 mm.

Self-tapping screw may also differ in its purpose. There are products for sheet metal, for metal profiles.

Probably everyone who had to buy screws noticed that the products may vary in color. It depends on what coating the fastener was treated with.

• Black - indicates that this is a phosphated or oxidized fastener. The phosphate-treated product is suitable for indoor use with high humidity. But the fasteners, on which a protective oxide film is applied, can be used in rooms with a normal humidity coefficient.
• Galvanized - treated with zinc coating. It is a versatile screw that can be used with metal in any environment.
• Yellow - in terms of parameters and properties, they are completely identical to galvanized ones.
• Product gray colors indicate that the screw has not been treated with any special coating. These fasteners are only suitable for indoor use.

When choosing screws for metal, several basic criteria must be taken into account.

1. What kind of metal will you work with?
2. Technical parameters of the fastener - size, thread pitch, quality of the head and tip of the end, length, thickness.
3. Color - the element must be of a uniform color.
4. The presence of marking is a prerequisite. It is she who testifies that the screw was made in accordance with the rules and regulations. The marking consists of numbers and Latin letters that indicate parameters such as length, diameter and weight of the product.

And pay attention to the type of product... There should be no damage or deformation on the screw.

You can find out how to properly screw the self-tapping screw into the metal from the video below.