Self-tapping screws for metal: description, types, sizes, characteristics, photos, videos

How to choose a drill for a dowel

There are also differences in the thread profile. Self-tapping screws have sharper and higher threads with different angles of inclination. Small drills are used for wood, large ones for metal. Self-tapping screws have a countersunk, semicircular head for a screwdriver or with a washer.

Differences, advantages

What is so good about self-tapping screws, because they are practically the same screws, but of a higher quality? Self-tapping screws are made using a specific technology. For manufacturing, only strong steel alloys are used, which undergo subsequent heat treatment. Otherwise, we can say that they are made of hardened steel. Like all steel fasteners, self-tapping screws for corrosion protection can be phosphated, oxidized or galvanized with passivation.

After such processing, the screws become characteristic black or brilliant white and acquire significant resistance to corrosion. For docking with the tool, they use clear and precise cross-shaped slots.

Self-tapping screws made of brass or stainless steel can be considered exotic.

Self-tapping screws with high screw threads have a thin and sharp profile. It is very easy to cut threads in sufficiently hard metals with self-tapping screws with such a thread profile. Moreover, its end is made in the form of a sharp cone. He, like an awl, makes a hole in the material for accurate installation and so that you can start threading. The work of the end of a self-tapping screw can be compared to the work of a drill. In some types of self-tapping screws, a kind of drill is formed at the end, which makes it possible to avoid drilling and threading. At the same time, it can be easily screwed into metal with a thickness of up to 2 mm.

Those self-tapping screws that are used to fasten various metal parts have more frequent threads. Quite often they have a two-start thread.

Universal self-tapping screws have medium pitch threads.

For fastening parts of wooden structures, self-tapping screws are used, which have a wide thread pitch, a large angle of inclination and a fairly sharp end.

The most popular self-tapping screws have a countersunk head that smoothly goes into a threaded rod. This form of fasteners is ideal for mounting drywall sheets. Self-tapping screws with a hex head are no less popular with us. Most often they are used when increased strength of fasteners is required. They are used together with plastic dowels to attach heavy objects to walls.

The roofing screw has a hex head, which goes into a large washer (press washer). It has a rubber gasket to seal the joint and is painted in one of the common colors of roofing materials (white, green, red, etc.).

Self-tapping screws with a semicircular head turning into a washer are used to join sheet-shaped materials. These sheet metal fasteners have fine pitch threads. At the same time, the shape of the head with an increased diameter makes it possible to more efficiently fasten the material by increasing the pressure to the base, when it is simply impossible to make a countersink.

Short self-tapping screws with a tip in the form of a drill and a semicircular head are used to fasten parts made of a metal profile. Very often they are called bedbugs and fleas.

Also, screws and self-tapping screws have differences in the preparation of the material for the use of fasteners. When using a screw, it is necessary to drill holes, where it is then screwed in. When using a self-tapping screw, the material does not require such preparation. The screws have only two types of heads.Self-tapping screws have a huge number of types of heads: several types of countersunk heads, hexagonal with and without a washer, semicircular with and without a washer, cylindrical and trapezoidal.

Self-tapping screws, due to their strength, are used for fastening all kinds of materials, from wood, plastic to metal, concrete.

We can conclude: the difference between a screw and a self-tapping screw is that screws require a pre-drilled hole, and self-tapping screws are suitable for almost all materials and do not require preliminary preparation of the working surface.

Types of stainless steel screw heads

Despite their identical functional purpose - holding the fixed objects - the screw heads are different. By their appearance, you can determine for what type of work this self-tapping screw is intended.

Reduced secret. It features a small bearing surface and a smooth transition from head to rod. After screwing in, it does not protrude beyond the surface of the material to be fixed.

Secret. The bearing surface is slightly larger than that of the previous species. Requires less effort during installation. Screwed in flush.

Concealed funnel-shaped with a thickening along the rod, for a 4 mm Allen key. It masks the connection well. After installation, the head is closed with a special colored decorative button.

Hemispherical. Has a good clamping area, which allows you to firmly hold the material to be fixed.

Hemispherical with a press washer. Designed for fixing sheet materials. With a reduced height, it has an increased clamping area.

Hemispherical with a large press washer. The bearing surface is very large, which is excellent for anchoring soft sheet materials.

Hexagonal. Has a good clamping area. Allows you to work with an electric tool with a hexagonal nozzle. Withstands high screwing forces.

How much do wood screws cost - an overview of prices for 1 kg

The price for wood screws is indicated by suppliers both per piece and per kilogram. But if you need to purchase, for example, 2000 pieces of such fasteners, no one will calculate them. Either they will be sold in their original unopened packaging, or they will be calculated by weight. In any case, consider the cost in several ways.

As you can see, the price of such fasteners is not that high in comparison with the benefits and convenience that they bring during use. In addition, even a beginner can work with them. It remains only to choose the right one and you can get down to business!

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Stainless self-tapping screws are widely used in various fields of activity. They are used in the construction industry, in the construction of buildings and structures. Used in the manufacture and assembly of cabinet furniture. Chemical neutrality and resistance to heat make these fasteners indispensable in the food industry, science and medicine. For corrosion resistance, they are chosen for use in various machines and mechanisms, used in shipyards and shipyards.

Confirmation stainless self-tapping screws are used only in furniture products - both in factories and in private production. With their help, secret connections are created in hull structures. Confirmate is suitable for fastening solid wood, MDF, chipboard to each other.