A small screw with a wide head. Self-tapping screws - types and sizes. The choice of self-tapping screw depending on the load

Everyone has done renovations at some time or plan to do so in the near future. And usually you can’t do without self-tapping screws, since they are considered an excellent fastening material for use on various surfaces. This may be wood, drywall or one of the metal versions.

The first two materials are easy and convenient to work with, but the last one is not as easy as it seems at first glance. It has a more rigid structure and not all self-tapping screws are able to overcome it.

So that you are not mistaken with the purchase, you need to figure out which metal screws are best suited for your purpose. They are sold by weight or by the piece, and are not expensive, but they usually require a lot of screws, so a useless purchase will hit the budget.

Based on various points of sale, they are called self-tapping screw elements - this explanation is necessary so that you are not mistaken and aware of what is at stake. Although sellers should understand you from the first words of the explanation, what a fastener is needed for.

By the way, it is worth consulting with them, as this is a sure way to buy what is needed for your purpose. If you choose on your own without the necessary knowledge, then you will have to face a mass of different options for self-tapping screws, differing in size, material, and shape.

You can look at the photo of metal screws, and make sure that it is difficult for an unprepared buyer to understand their diversity. Because of this, we will fill in the gap in your knowledge so that you understand why you are buying this fastener. Consider the various types of self-tapping screws, and especially focus on those designed to work with metal.

Self-tapping screws for working with metal

They are of two types, and differ in some nuances. Let's look into them:

Self-tapping screws based on a pointed end are very similar to the classic type of screws popular in Soviet times. They are created using quality metal, and are supplied with successive threads with little inter-ridge space between them.

This is necessary to increase the quality of adhesion with a very hard type of surface - various metals. This species has the following characteristics:

• The diameter is offered in the region of 3.5 - 5.0 mm, and its level increases closer to the screw head;
• The length is usually around 10 - 50 mm based on threaded application in 5.0 mm increments;
• If the length reaches 60.0 - 100.0 mm, then the thread pitch will be in the region of 10.0 mm;
• Based on 110.0 - 120.0 mm will be about 15.0 mm;
• And with a length of 125.0 - 220.0 mm, threading is usually offered in increments of 20.0 mm.

Important: Now many manufacturers have appeared, and sometimes they produce self-tapping screws of this type with other parameters based on their own vision of their dimensions. Because of this, any version of such a fastener can be found on sale.

If you need to fasten something to metal with a thickness of 2 mm, then you do not need to create a preliminary socket, since a specialized self-tapping screw will do the job.

And, if the thickness turns out to be greater, then create a passage with a drill having a diameter less than that of the fastener by about 2.5 mm. Due to this, it will be possible to achieve a tight connection of the part with the metal.

Make no mistake and choose the right self-tapping screw for working with metal. For the manufacture of this type, a very durable metal is used, which has a galvanized or oxidized coating. They are found on the basis of metallic, gold or black.

Self-tapping screws with a drill bit are equally useful, as they are used for a slightly different fastening purpose. But in general, they are almost the same as with a pointed end. But there are a number of differences:

• Has a drill tip
• The hat is offered in the form of a cone or a press washer.

This look does not need to be pre-nested as it will easily fit into any metal and provide an excellent bond. This is facilitated by the unique shape of the cap of the fastener.

What is interesting about the option with a press washer?

If you remember, we have already mentioned self-tapping screws with a press washer, but, nevertheless, we will create a separate description for them, since they differ in the large size of the contact area of ​​\u200b\u200bthe cap. And due to this, they stand out noticeably among other types of self-tapping screws.

With the help of a special design, this fastener perfectly fastens various forms of wooden slats and metal sheets with a thickness of 1.1 mm. But outwardly, it almost does not differ from its analogues, since it is not supplied with a unique color, and usually has a silver color.

Only a professional who constantly works with them during various construction activities can figure out which self-tapping screw in front of him.

And what about the hexagonal view, why is it interesting?

All photos are clickable, for a detailed view, click on the photo.

Self-tapping screws are a thing that is simply necessary in construction, you cannot do without it if you decide to hang a shelf, wardrobe, picture, assemble furniture, build a house. There are a lot of types of self-tapping screws, as well as building materials for which they are intended. Let's consider the most common ones. For tightening, you need screwdrivers or.

Wood screws.

Their main distinguishing feature is a rare thread pitch. The distance between the threads is noticeably greater than, for example, for metal screws. This is due to the fact that wood itself is less dense and harder than iron. They can be black, white, golden colors, depending on the color of the material you are working with. The most commonly used color is black. If you need to fasten, for example, a yellow furniture hinge, of course it is better to take a self-tapping screw to match.

The length of the screws. From the shortest 11mm, the so-called seeds, they got their name because of their small size, about the size of a sunflower seed, to the longest 200mm.
You need to select a self-tapping screw so that the connection of the parts is tight. For example, if you are fastening two bars at 50mm, take a self-tapping screw with a length of at least 75mm, 90mm is also possible.

The diameter of the screws. Black self-tapping screws (the most commonly used) have a diameter of 3.5mm, 4.2mm, which allows you to tighten them without pre-drilling.
Yellow have a diameter of 2.5 - 6mm.

Holes for screws will be required if the diameter of the self-tapping screw is 4.5 mm and above. If the bar or workpiece is thin, you can drill a hole for 4mm hardware.
A 4.5mm hole will require a 3mm-3.5mm hole, depending on the density of the wood.
Under the 5mm self-tapping screw you need a hole of 3.5mm-4mm.
For 6mm - 4.5mm, then the wooden blank will not crack. Use a regular metal drill, as wood drills with a 0.5mm pitch do not exist.
Too large a hole should also not be drilled, otherwise the adhesion density will be low.
For black ones, you will need a screwdriver with a PH #2 connector, or the same bit. For yellow

bit PZ No. 1, No. 2 or No. 3, depending on the diameter of the self-tapping screw.

Self-tapping screws for metal.

As a rule, they have a frequent pitch, the distance between the threads is very small, unlike wood screws. A frequent stride is required for dense material to ensure good grip.
Black self-tapping screws for metal have a diameter of 3.5mm. If you are screwing a thin tin, then you can not pre-drill. If the thickness of the workpiece is 2mm or more, you need to make a hole of about 2.8-3mm.
They have a PH #2 connector.

Self-tapping screws with a press washer galvanized sharp(PH connector #2).

Allows you to fasten sheet metal up to 0.9mm without drilling a hole. Also suitable for fixing wood.
A large cap allows you to press the material to be fixed more tightly, it serves as a washer. They have a diameter of 4.2mm, length from the shortest at 13mm, to the longest at 64mm.

These can be used to fasten metal up to 2mm without drilling a hole. A drill is located at the end, as if for itself, it drills a hole and twists.
For these, bit PH No. 2 is required.

Designed for fastening roofing materials, as the name implies. Diameter 4.8mm and 6.3mm. Length from 19mm to 100mm. There are different colors, depending on the color of the material, blue, brown, just galvanized.
For these, you will need a bit with an 8mm hex socket if the diameter of the screw is 4.8mm, and 10mm if the diameter of the hardware is 6.3mm.
It has a rubber gasket to keep the roof from leaking.

Furniture self-tapping screw (confirmat).

Used when assembling furniture, length 50mm, requires pre-drilling. There is a special drill for it, for two diameters, since its thickness is at first the same size, towards the end there is a thickening.
You will need a 4mm hex wrench if you twist by hand, or a bit for a screwdriver - HEX 4.

Screw with hex head(sometimes called capercaillie).

Screw with hex head

This is perfect for heavy structures, where special strength is needed. Designed for wood, has a thickness of 6mm-10mm. Be sure to drill a hole for it before screwing it on. For a 6mm screw - 4.5mm, for 8mm - 6mm, for 10mm - 7.5mm-8mm.
To tighten such self-tapping screws, you will need a wrench, the hat has a hexagonal shape with a diameter of 10mm, 13mm, 17mm, depending on the thickness of the screw.

If using a self-tapping screw with a dowel, then select the dowel so that its diameter is approximately twice the diameter of the self-tapping screw. For example, if the self-tapping screw is 3.5mm - the dowel is 6. If it is 4mm or 4.5, then the dowel is 8mm.
Make a hole in the wall in the size of the diameter of the dowel.

Among the most popular and reliable fasteners, self-tapping screws are used most often in a variety of repairs and connections. The work that is done with self-tapping screws is usually done quickly and efficiently, and also simply even for an amateur. The standard designation for self-tapping screws is the number 325, in which 3 indicates the outer diameter of the thread in mm, and 25 indicates the length of the self-tapping screw from its very head to the sharp tip.

There are self-tapping screws for concrete, which differ in the screwing method, which does not require the presence of a dowel, but they themselves are screwed directly into the drilled hole. If we are talking about a porous material, then it is not recommended to drill holes for self-tapping screws with a puncher, and to make it easier to tighten the self-tapping screw, it is necessary to inject quite a bit of machine or any other oil into the hole.

There are also varieties of self-tapping screws that have a special thread profile called herringbone. Such self-tapping screws are usually hammered directly with a dowel and used for fastening almost “forever”. Usually such self-tapping screws are used for fastening special baguettes on French stretch ceilings or during the installation of metal-plastic windows. The main advantage of such self-tapping screws is quick installation.

Another type of self-tapping screws is their difference in the type of head. Among this category, self-tapping screws are usually distinguished in the form of: hexagons, hemispheres, sweats or half-cylinders. Which type of self-tapping screws to use when carrying out a certain type of work will always depend on the quality or density of a certain type of material.

Varieties of self-tapping screws

Among the varieties of self-tapping screws, the most common:

• By wood;
• For different types of metals;
• Window and door;
• Roofing;
• For drywall;
• For special gypsum fiber sheets;
• On drywall with a special drill;
• On drywall with a particularly large thread pitch.

Self-tapping screws for wood

This type of self-tapping screws is mainly used in the manufacture of furniture products or other wooden structures. The head of such wood screws is made in the form of a hexagon, which also has a hidden shape. As a rule, the thread of this type of self-tapping screw has a wide pitch, which facilitates their screwing in and secure fastening of the joints. To install and fix wooden frames, bows or fittings, as well as to install special wooden profiles on windows, they use the same self-tapping screw, only with a two-thread thread and a head that has a special cross-shaped slot with sweat.

This type of self-tapping screws is used to fix any materials or structures to a metal profile, pipe or sheet. Moreover, the tips of such self-tapping screws can usually be of two types: either in the form of a reliable drill, or with a sharp tip. Self-tapping screws for metal can have different heads, namely:

• Press washer;
• hemisphere;
• Hexagon.

Most often, metal screws are made of carbon steel, and to extend their quality service life, especially at high humidity, they are subjected to a special treatment called phosphating or galvanizing. In retail outlets, metal screws are usually presented on special stands, indicating a two-digit marking. For example, the designation 3.5 by 35 means that the diameter of this self-tapping screw has a size of 3.5 mm, and its length is 35 mm. The industrial production of self-tapping screws for metal is focused on the following values: thickness from 3.5 to 4.8 mm, length from 11 to 300 mm.

Such self-tapping screws are used mainly for wooden products and they usually have a thickness of 6 to 10 mm. In order to screw in such a self-tapping screw, a special hole is drilled in the product, with a diameter of 1.5-2 mm less than the self-tapping screw itself. To tighten such a self-tapping screw, you will need a wrench or a head with a diameter of 10, 13 or 17 mm. If a self-tapping screw with a dowel is used, then the dowel must be chosen at least twice the diameter of the self-tapping screw itself.

For example, if the self-tapping screw itself has a diameter of 3.5 mm, then the dowel will have a diameter of 6 mm. A hole in the concrete wall for such self-tapping screws is made according to the diameter of the selected dowel. If it is necessary to fix profile guides or aluminum corners, as well as attach a picture, a carpet plank or something similar to the wall, then plastic dowels are used for this, 6/40 or 6/60 in size with a “fungus” or “sweat” cap. ". For such fastening, it is necessary to drill a neat hole in the wall corresponding to the diameter of the dowel of this self-tapping screw, for example, with a 6 mm drill. Then a dowel is inserted into the hole, into which the self-tapping screw is hammered or screwed.

So, the main difference between standard self-tapping screws and screws is that the latter are used for fastening to wooden structures. Wood screws require holes to be drilled. But self-tapping screws are perfect for fastening to a more durable base, such as metal, concrete, stone or brick, which most often does not require pre-drilling holes.

Anchors are one of the types of fasteners for secure fastening of heavy or bulky objects, by reliably wedging fasteners directly into the wall. An anchor bolt is almost the same fastener as a dowel, screw or self-tapping screw, but its main difference is that the dowels of the anchors are made of metal, and the screw itself has a metric thread that is screwed into the nut. The nut itself, which enters the tubular hollow base of the anchor bolt, pushes it apart, making its connection to the wall practically dead.

Anchors are used exclusively when working with a solid base or material, such as a concrete wall, brick, cinder block or natural stone. In domestic conditions, anchors are usually used when attaching chandeliers, boilers or French stretch ceilings of a large area. Anchors are also used for reliable fastening of a variety of sports structures, such as rings, horizontal bars or wall bars. And if it is decided to fix a children's swing, then powerful anchors are the best option.

All photos from the article

What can be the length of wood screws and their diameter? Why do they differ in colors? What type of self-tapping screws has the highest mechanical strength?

Where and why can they be used? Is it possible to somehow reduce the force required to screw in this fastener? Let's figure it out.

Varieties

A characteristic feature of the main part of wood screws is a large thread pitch. Fine carving is used only for especially hard wood.

Self-tapping screws can be conditionally classified according to three parameters.

Colour

Black (phosphated) products have a rough surface and, as a result, good adhesion to wood.

Note that the downside of a good grip is the relatively high force required to screw in the hardware.

Black hardware for woodwork is twisted, as a rule, with a PH2 bit or a regular Phillips screwdriver. And [the main drawback is limited resistance to corrosion: despite the phosphating layer, in a humid environment, the caps will quickly decorate the surface of the wood with untidy rusty streaks.

Yellow (brass-plated) fasteners have increased corrosion resistance and slightly weaker adhesion to wood (brass is a metal with a low coefficient of friction). Due to the relative high cost of the brass passivation process? their price is higher than that of phosphated ones. The hat is compatible with RZ bits.

White self-tapping screws differ from yellow ones only in the way of anti-corrosion protection: they are covered with a thin layer of zinc. There are no functional differences between white and yellow hardware; the choice of one or another is reduced to the selection of the color of the surface.

Head

The shape of the hat can be distinguished:

• Countersunk (conical head) with a cross slot. All black screws are countersunk.

• Countersunk with slot(for a flat screwdriver or bit). They are not very popular due to more stringent bit quality requirements and a greater likelihood of breaking splines when screwing in compared to cruciform counterparts.
• With press washers (a kind of semi-hidden; they provide reliable pressing of the part to a wooden base with pressure distribution over the maximum surface).
• With press washers and rubber seals. This type of hardware is in demand in cases where it is necessary to ensure the tightness of the connection. The most typical example is the fastening of a profiled sheet to the roof lathing.
• Hex head. In addition to the shape of the head, they differ in significant thickness; consequently very durable. Usually zinc plated.

Curiously: in the absence of a powerful screwdriver with the appropriate bit, hex-headed products are screwed in with an ordinary open-end wrench. They often successfully replace anchors; in particular, toilet bowls and wall-mounted sinks are equipped with fasteners of this type.

Thread length

It may be complete (from tip to cap) or incomplete, with a smooth area in front of the cap.

1. The first version is useful in that it provides maximum joint strength when attaching a thin metal part to a wooden base.
2. The second is used when fastening relatively thick wooden parts (for example, counter-lattices for vapor barrier when assembling a roofing pie).

Dimensions

The standard sizes of wood screws are different for each variety.

Phosphated, countersunk heads and cross slots

Yellow and white countersunk heads with cross recess

Countersunk head with slot

Manufacturers indicate the dimensions of these products in a somewhat unusual way: for them, the diameter of the head and the self-tapping screw are given separately.

Diameters can be combined in the following options:

• 16*8;
• 12*6;
• 10*5;
• 9*4,5;
• 7*3,5;
• 5*2,5;
• 3,2*1,6.

Hex head

The longest wood screws belong to this category. Here is a list of fastener sizes:

With press washer

The maximum dimensions of self-tapping screws with a press washer for wood are relatively small due to the specifics of their application: they are intended primarily for fastening thin sheet materials to a wooden base.

We hope that a small instruction on handling fasteners will be useful to the reader when assembling various wooden structures with his own hands.

• A 35 mm wood screw is ideal for attaching drywall to. Fasteners are screwed in increments of 15 - 20 cm after marking the position of the bars on the surface of the GKL; the heads are recessed into the drywall by about a millimeter and, when puttying the seams, are sealed with gypsum putty.

• Black wood screws 35 millimeters long are also perfect for sheathing or OSB. The holes for them in the sheet material are pre-drilled with a diameter equal to the outer diameter of the fastener thread. Then the holes are countersunk with a drill, the diameter of which is equal to the size of the cap.
• A wood screw 51 mm long is suitable for two-layer plasterboard sheathing of the wooden frame of the partition during the fastening of the second layer. Double skinning is necessary in small rooms with high traffic.
• Self-tapping screws for wood 75 mm and longer cannot be screwed into wooden parts without first drilling holes with a smaller diameter of 1 - 1.5 mm. Otherwise, there is a risk of splitting the tree into fibers.
• If you have to drive wood screws 100 mm or longer into dense wood, pre-drilling may not be enough. The screwdriver simply will not be able to turn the hardware on the last turns. A simple trick will help here: drop a little of any oil (for sewing machines, mineral or even mining) into a pre-drilled hole.
• Plywood with a thickness of more than 15 mm can be butt-jointed at right angles, without corners or bars; moreover, such a connection will be noticeably stronger than using the same furniture corners. Holes equal to the diameter of the self-tapping screw are drilled in the plane of one of the parts; at the end of the second part - with a diameter of 1 - 1.5 mm less.

The size of the hardware depends on the thickness of the parts to be joined: 51 mm fasteners are suitable for 15 mm; a 75 mm wood screw can be used with 22 mm plywood.

• To seal recessed hats on the front surfaces of the parts, you can use acrylic wood putty; however, it is difficult to match it exactly to the tone of the wood. Another way is much more practical: mix the sawdust remaining after drilling with a small amount of PVA glue - and you will get a putty that, after the glue has set, will exactly match the color you did.

Screws, screws, bolts - these types of fasteners have been used for a long time, but there are also self-tapping screws. What is it and what are their features? What are the types of screws, how to choose them?

How is a self-tapping screw different from a screw

Let's start with definitions. A screw is a fastener with an external thread applied to the rod. When joining parts, the male thread of the screw aligns with the female thread on the hole in the part or parts. So for the installation of the screw, you must pre-drill a hole. A screw differs from a screw in that it has a smooth tapering at the end and more rare threads.

What is the difference between a self-tapping screw and a screw: thread and material

And now attention. Self-tapping screw is short for self-tapping screw. It differs in that it does not require a pre-drilled hole for installation. When screwing in, he himself cuts the required grooves. Hence the term self-tapping. And so that the self-tapping screw can "bite" into the material itself, its thread is triangular, with sharp edges and, as a rule, more "deep". So, a self-tapping screw is a type of screw that itself drills a hole in the material as it is twisted.

A self-tapping screw is a screw that drills a hole for itself.

If we talk about the difference between self-tapping screws and screws, then the self-tapping screw has a more elongated and sharp edge. With this form, it is easier to "bite" into the material. To install self-tapping screws, a screwdriver is usually used, which allows you to do a large amount of work, unlike using a conventional screwdriver. It is not easy to overcome the resistance of the material when cutting a hole.

Types of self-tapping screws

Self-tapping screws are divided according to the field of application. They are universal, for wood, metal. These are the three main and large groups. There are even more highly specialized ones - for concrete, drywall (GKL) and. There are separate groups for window profiles and roofing materials.

However, keep in mind that if they talk about self-tapping screws for metal, they mean sheet metal or profiles from it. And then, in sheets of large thickness, holes are often pre-drilled. It is easier and faster to install fasteners, especially if they do not shine with quality.

There are many types of self-tapping screws. So which ones to choose?

Moreover, holes are often drilled in wood for self-tapping screws. In dense wood - such as oak - this is almost an immutable rule. The density of such wood is high and otherwise the process is too slow. In soft wood, holes for the installation of self-tapping screws are drilled for a different reason - so that the tree does not crack. When the screws are placed almost on the edge, this is possible. Here they are insured. In any case, the diameter of the hole for installing the self-tapping screw should be 1-2 mm smaller than the diameter of the fastener. Only under this condition will it be easy to install, and the strength of the connection will be normal.

There are also universal screws. But this does not mean that they are “for everything”. This means that they are optimal when you need to combine wood and metal. And for connecting metal-metal, wood-wood - it is better to take your own narrow-profile fasteners.

For wood and metal - the difference

What is the difference between self-tapping screws for wood and metal? First of all - different thread pitch. For installation in a tree, the carving is more rare. This is quite enough to gain a foothold in the fibrous structure. The self-tapping screw for metal has denser threads. Another difference is in the metal used for the manufacture of fasteners.

What is the difference between wood screws and metal screws. The first thing that catches your eye is the density of the thread. The second is the diameter of the pin, the third is the height of the thread profile

Even self-tapping screws for metal can have not just a narrowing with thread, but additional planes - a drill. Such fasteners can drill holes in sheet metal up to 5 mm thick. So that the edge of the self-tapping screw does not slide over the surface of the metal (and wood, too), the installation point is “punched”. With the help of a punch and a hammer, a small dent is left. It is not necessary to punch through the metal. It is enough that the screw of the self-tapping screw falls into the recess.

Metal and processing method

Self-tapping screws are made of carbon steel, stainless and brass. In the vast majority of cases, we use self-tapping screws made of carbon steel. They are not as expensive as stainless steel, but quite durable if you choose the right one. However, steel self-tapping screws can be of different colors: white, yellow and black. They are dyed after processing. Blacks are obtained by oxidizing and phosphating, yellows are obtained by anodizing, and whites are usually galvanized. There are also yellow galvanized ones.

You also need to keep in mind the way the metal is processed.

What color self-tapping screws is better to choose? Looking for what material. If for wood, the best choice is anodized. These are yellow. Yes, they are much more expensive than black ones. But black oxidized rust and then leave streaks on the wood. For metal, this is not critical, since usually the joints are painted over so that they do not rust. But there is another point: black oxidized self-tapping screws can be brittle. If you “twist” it during installation, the head may fly off. Not only can this happen during installation, it also happens under load. For example, when the flooring was screwed to the logs with black oxidized self-tapping screws. Boards are known to bend and dry out. And this leads to increased loads on the fasteners. And the hats of black screws often fly off. This can be seen when the bulkhead floor. And also by the fact that some boards begin to bend or sway and creak more strongly. Hats broke off and fasteners do not hold.

To install metal sheet material, it makes sense to take galvanized self-tapping screws. There will be no conflict of coatings and chemical reactions. In this case, they usually take white. Yellow is used for aesthetic reasons - when installing door hinges, locks, handles and other similar yellow accessories.

Types of self-tapping screws: head and slot

More self-tapping screws are divided by type of head. There are many types, but it is worth remembering that there are secret, semi-hidden and protruding (hemispherical, semi-cylindrical, etc.). Also available with hex heads. They are used to install roofing material, polycarbonate, fastening materials to fences, sheathing frames. In general, where rigid fixation is important. It is the screws with hexagonal heads that are usually equipped with sealing washers with rubber gaskets.

Types of self-tapping screws

Self-tapping screws with countersunk heads are hidden in the wood during installation. In this case, it is not necessary to pre-drill holes of a larger diameter for the cap. To make the hat “like clockwork”, take hidden heads with notches.

Types of slots on self-tapping screws. It makes sense to take those for which you have a tool

The caps have a recess for the tool - this is the slot. This parameter is selected based on the available tool or bit. You can, of course, buy them - beats - but you should think about it in advance. And then buy fasteners and bits. If we talk about which slot is better, then at the moment it is considered the best Torx (torx), as it transmits torque best. This is important when working with hard material.

Choice of screw length

There are several rules for choosing the length of a self-tapping screw, which are used in different situations. When rallying / connecting two not very massive parts, the following selection rules work:

If some thin detail is attached to a massive base, another rule works. Then the length of the fastener should be 2-2.5 times longer than the attached part. So you need to select the length of the self-tapping screw, if you fasten something to the wall, say, or to the concrete floor. In this case, to fix the same 28 mm board to the wall, the fastener length is 56-70 mm. Here is such a difference.

Self-tapping screw sizes: the most applicable options

How to choose the length of the screws, it seems to be clear. Now about what they generally are. Here the situation is confusing. Neither screws nor self-tapping screws have a common standard. There are several standards for “worn out” years of manufacture, which specify the dimensions of some types of self-tapping screws.

• GOST 1145-80. Self-tapping countersunk head screws.
• GOST 1144-80. Screws with a semicircular head.
• GOST 1146-80. Screws with semi countersunk head.

The situation today is such that each manufacturer produces its own "line". They are oriented, of course, to demand. Well, the parameters of the heads are usually made in accordance with one or another GOST. This somehow stabilizes the situation. Sometimes the assortment - diameters and lengths are also made according to the standard. In this case, in the description of the self-tapping screws, the diameters in which they are generally produced are indicated, and then there is a postscript: it corresponds to such and such GOST. This means that the heads correspond to the specified standard, and also that the assortment corresponds.

Diameters and lengths of self-tapping screws with countersunk head GOST 1145-80 and semi-counter head GOST 1146-80

How then choose self-tapping screws in length and diameter? Calculate / determine the length that is needed, determined with the type of head. Then they look at the diameters and make the final choice. Let's say right away that for wood the principle "thicker means better" does not work. This can be applied to metal. For wood, thinner ones are better, but with good carvings and from good metal. Here is the ideal option.

If the parameters of the self-tapping screws from the manufacturer are "their own", they are indicated in the description

But this is not enough. The store usually offers up to a dozen options of the same size, but from different manufacturers. And if it is more or less easy to decide on the metal and the type of processing, then it is difficult to choose which brand to take. There are, of course, proven ones, but they are expensive. Although, if you take cheap ones, 30-50% can go into marriage. What marriage? Then they bend, then the hats fly off. It's not always, but often. If you are “lucky” to run into such fasteners, it turns out that buying “expensive” ones would not be more expensive. Well, not much more expensive.

Lengths and diameters of self-tapping screws with a semicircular head according to GOST 1144-80

Now compare the two tables. They are compiled according to different GOSTs. As you can see, the diameters and lengths match. This is what makes life easier. If in the manufacture of fasteners they adhered to the standard in terms of the ratio of diameter / length, then everything is simple. If not, then the manufacturer in the description of the screws attaches a table with dimensions (as in the figure above).

It is not necessary to use self-tapping screws for metal or universal screws for fastening wood. Universal are good when you need to twist wood and metal. And when twisting two pieces of wood, they work worse. In the sense that specialized fasteners will hold the wood better. That is, we consider only wood screws. Believe me, there will be plenty to choose from.

Wood screws are better yellow (yes, expensive) or white (slightly cheaper)

As already mentioned, wood screws have a rarer thread with a higher profile (the grooves between the turns are deeper). They are used not only for wood, but also for all types of sheet materials: GVL, plywood, OSB (OSB), fiberboard and chipboard. Now about when which ones work best.

Carving and other "bells and whistles"

First you need to choose the type of hat. Secret or with a press washer, cylindrical, hemispherical - choose based on what kind of connection you need to make. It is also recommended to choose a TORX type spline, as it best transmits torque from a power tool. Next in order.

Are these bells and whistles necessary or is it a waste of money? As for the incomplete thread - this is not news. "Sits down" one detail on another is much denser. And try the rest. Only on your own experience will you understand whether it works or not, and what specifically suits you best.

And practical advice on choosing wood screws. It is important that the thread goes immediately from the very tip. If the first turn is too far or the tip is blunt, do not take it. There will be continuous torment, not work.

The choice of self-tapping screws for metal

Types of self-tapping screws for metal are more numerous, so understand and understand. They are definitely not made of brass - the metal is too soft. Self-tapping screws for metal are made of carbon and stainless steel. All types of heads are present, slots are also almost all available. There are two types of tips - with a sharp end and a drill. They are also divided according to the area of ​​\u200b\u200bapplication - for indoors and for the street. They differ in the thickness of the protective layer. For the street, the coating should be thicker. Consider the most common types of metal screws.

The most popular types of metal screws

Self-tapping screws with a press washer (seeds)

They differ in the head - it is wide and flat. A roller is formed along its edge, which presses the parts. This type of hardware is used not only for fastening sheet metal and products from it (for example, they assemble a frame for drywall). It can also be used if you need to fix plastic, plywood or fiberboard to wooden bars, metal or wooden frame. The flat and wide head presses materials well at the junction.

This is what self-tapping screws with a press washer look like

If you look closely at the head of the fastener in the photo on the right, you will see that the part has a rounded and almost flat shape. By the way, most of them are in stores and on the market. But this is not the best option for this fastener, although it is cheap. There are very few decent products of this kind. Often the slot is small, untreated metal that breaks or bends. But the most important thing is that even white galvanized self-tapping screws have a very thin layer of galvanization - 3 microns. It quickly collapses and the metal begins to rust.

Self-tapping screws with a press washer are produced in only one diameter - 4.2 mm, but the length can be different

If you look at more expensive metal screws with a press washer (pictured on the left), they have a trapezoidal head. It is higher, which allows you to make a deeper slot. They are also called "reinforced". The quality of such fasteners is much higher. A deeper spline contributes to better torque transmission. This makes it possible, even without increasing the size of the self-tapping screw, to draw parts more tightly. For what? Due to the fact that the reinforced design can withstand more torque.

The sizes of self-tapping screws for metal with a press washer are not encouraging. Usually there is only a diameter of 4.2mm, and the length can be 13, 16, 19, 25, 32, 38, 41, 50, 57, 75mm. The package weight depends on the number of pieces. It can also be one of the criteria for assessing quality. In any case, the density of the metal and how accurately the dimensions are maintained. Because very often the rod is made not 4.2 mm, but 3.8-4.0 m, also in length. And the cap is thinner. In general, pay attention to the weight of the screws.

Self-tapping screws for GKL profiles

These are small black hardware. Sizes do not indulge in variety. There is one diameter - 3.5 mm and two possible lengths - 9.5 and 11 mm. For their small size they are called "bugs". They are made of steel with zinc coating or phosphating. The head is a truncated cone, the slot is cross-shaped. A notch may be applied to the underside of the head. It serves for braking - it starts to cling to the relief on the self-tapping screw, which disables the rotation of the screwdriver.

Appearance and drawing

The screw is pointed, there is a screw. Despite their small size, they drill metal up to 0.9 mm thick, and fasteners with a drill - up to 2.0 mm. But this is if they are of normal quality. Please note that this fixture is designed for indoor use. On the street, it quickly begins to rust, so do not use it outside.

Black self-tapping screws for fastening the plasterboard to the frame

The frame for drywall is assembled using "bugs" or self-tapping screws with press washers. The sheets themselves are attached to the frame using black self-tapping screws with a countersunk head and a sharp end. Made from phosphated steel, there are also galvanized. Actually, these are self-tapping screws for wood or metal. What to take to attach the GKL? Depends on what kind of frame you have. For wooden bars, take wood, for profiles - metal.

This is what self-tapping screws look like for attaching drywall sheets to the frame

If you are plasterboarding a normal living space, black phosphated screws are a good choice. If the frame is assembled in the bathroom, kitchen, toilet, it is better to take galvanized ones. With high humidity, black ones quickly rust, then the heads fly off.

The most popular sizes of drywall screws that are attached to a wooden crate

What are the dimensions of the drywall screws? The optimal diameters are 3.8, 4.0 and 4.2 mm. The length can be 16, 19, 25, 32, 35, 41. 45, 51, 55, 61, 65, 70, etc. up to 100 mm. What is the length of the self-tapping screw needed to attach the GKL sheet to the profile? Use the universal rule: double the length of the attached material. If you fasten drywall with a thickness of 12 mm, then the self-tapping screw is not shorter than 25 mm. Can it be longer? It is possible, but why?

Roofing screws

This is a type of fastener for outdoor use. This means that the protective layer is thicker. Roofing screws are easy to distinguish by their appearance. They have a hex head and a sealing washer. The washer can be rubber or silicone. Silicone is much more durable, but also more expensive. Good rubber, by the way, can also not crack for decades. It's hard to tell if it's good or not.

Roofing screws are of different types and they are designed for fastening different materials to frames of different rigidity. There are such types of roofing screws:

Types of self-tapping screws for the roof and their area of ​​\u200b\u200buse

• Pointed. Designed for fastening soft material to a wooden crate.
• With short screw. This type is for fixing metal sheet material to wood.
• With long screw. This is for metal-to-metal fixation. It is most often used for fastening the profiled sheet to the frame of the fence.

Length and diameter of roofing screws of different types

Roofing screws are made of galvanized steel. And it is better if galvanizing is galvanized. This coating is more durable. On top of the galvanized paint is sometimes still applied. Color - in tone with a coating. Washers are made either also galvanized or aluminum alloy. The washer was said to have a rubber or silicone seal. Rubber is better than EPDM, it does not lose elasticity for a long time even in the open air. The running dimensions of the roofing screws are given in the table.