4 tips for choosing self-tapping screws: types of screws, sizes, purpose

Content

1. 1. What is a screwdriver?
2. 2. Types of screws

• Material of manufacturing self-tapping screws
• Self-tapping
• Self-tapping design

3. Appointment

4. How to choose the "right" self-tapping screw

For sure, at least once in your life you had to fix something or screw it yourself. It's no secret that special accessories are needed for this, and the choice of all kinds of nails, gadgets, screws, self-tapping screws and other fasteners, in modern construction stores very impressive! You stand, you look and just your eyes run. Any person, for sure, will be lost in such a store, but for this not to happen to you, we suggest that you consider in detail such kind of accessories like a screwdriver, and figure out how to choose the screws, what they are and for attaching which materials can used.

1. What is a screwdriver?

Screwdriver- a fastening element in the form of a rod with an outer triangular sharp thread and a head that, while twisting, also cuts the thread in the element to be joined. Samoraz managed almost completely

replaceordinarynails, because the connection with their participation is much more reliable, self-tapping can be connected not only with the tree, but with many other materials, besides, you do not risk injury during work.

2. Types of screws

Material of manufacturing self-tapping screws

• Carbon steelIs an alloy of iron with carbon without any impurities. It has high strength.
• Stainless steel- steel with a chromium content of at least 10.5%, which makes it corrosion resistant and very durable, stainless steel will never be rusted and has an almost unlimited lifespan, besides, they are the most Cheap. Stainless steel products also have hygienic properties, which makes it possible to use them even in medicine.
• BrassIs a copper alloy with the addition of zinc, sometimes tin, nickel, lead, manganese or iron. Brass screws proved to be very reliable and wear-resistant. In addition, brass has non-magnetic properties, anti-corrosion properties and is resistant to low temperatures.

Self-tapping

• Phosphated(black) self-tapping screws are made of carbon steel with subsequent treatment with phosphates. Used in rooms with high humidity.
• Oxidized(black color). These screws are made of carbon steel with a protective oxide film. Suitable for use in rooms with normal humidity.
• GalvanizedSelf-tapping screws are also made of carbon steel, followed by zinc coating. Suitable for indoor and outdoor use.
• Galvanized yellowSelf-tapping screws differ from the previous ones only in color, they are used mainly for door hinges of decorative gold color, as they are visually less noticeable against their background.
• Without cover.Used for interior work at normal humidity.

Self-tapping design

Head (1)

This is the upper part of the screw, with the help of which torque is applied. There are different forms:

• Secretthe head of the self-tapping screw is completely drowned and does not protrude above the material being fixed.
• Half-hiddenthe head has a smooth transition from the stem to the thread and, when curled, is buried in both the material and the mating part. This allows you to apply more force when twisting.
• Semicirclehas a large pressing surface, due to which the fastened element is more firmly held.
• Semicircular with press washerUsed for fixing sheet materials, has an increased area of ​​the bearing surface and a reduced height.
• Truncated cone ("flea")It is used for fastening metal profiles, sheet metal, gypsum boards. Such screws have a phosphate coating.
• HexagonalThe head allows you to twist the screw with a power tool with a special nozzle.
• Cylindricalthe head has screws that are screwed into the pre-drilled hole.

Thread (2)

• Rare. Self-tapping screws with a rare thread use for fastening soft materials without the use of dowels, for example for wood, gypsum, plastic, asbestos. Possible thread diameters - 3.5-5.0 mm, length - from 16 to 150 mm.
• Averagethread is universal, designed for all kinds of fasteners. Thread diameter from 3.0 to 6.0 mm, length - from 12 to 220 mm.
• Medium with a fur-tree profileIt is used for fastening to a concrete or brick surface by a method of plugging into a dowel. Thread diameter - 5.0, 7.5 mm, length - 40, 50, 60, 70 mm.
• Frequentthread is used for fastening to metal sheets up to 0.9 mm thick without the use of dowels, but with preliminary drilling, can have a drill bit on the tip. Thread diameters 3.0 - 8.0 mm, length - from 12 to 200 mm.
• AsymmetricThe carving is intended for fastening elements of furniture made of wood, chipboard, plywood. Preliminary drilling is necessary. Thread diameter - 5.0, 7.5 mm, length - 40, 50, 60, 70 mm.

Tip (3)

• AcuteThe tip is used to connect soft materials, its sharpness is enough to start spinning by simply sticking it into the surface.
• DrillThe tip is used to work with metal, when screwing, first drill a hole on the surface of the metal, and then, directly, the screed of the two elements.

Slot (4)

This groove is of a special shape on the end of the head.

• Straight and crossthe slot option are the most common options to twist such a screw, it is enough to have a suitable screwdriver or screwdriver with the appropriate attachment.
• HexagonalThe slot can be external or internal. The outer is twisted with a special key with a nozzle, which allows you to exert more effort to tighten the elements. Internal - a regular hexagon, suitable size. Also in the internal hexagon, which is used for fixing furniture elements, you can insert a special plastic plug for the color of the product, so that the screw does not spoil the aesthetic appearance.
• Torx- a kind of slot in the form of a six-pointed star. Twisted with a special key, or a screwdriver with a suitable attachment.

3. Appointment

• UniversalThe screw has a countersunk head with a cross-shaped slot and a sharp tip. Has a galvanized coating. Can be used both outdoors and indoors, suitable for finishing in wet rooms. It is used for fastening wood, plywood, particle board, sheet metal (with pre-drilling), artificial stone and other materials. They have a length of 12 to 200 mm, thread diameter from 3 to 6 mm.
• For wood.Wood screws are used to join plywood, wood, and their varieties. Fixing wooden products with self-tapping screws is muchstronger, than the fastener, made by nails, it is conditioned by the presence of thread. Even after a long timespontaneous twistingself-tapping screwwill not happen, as happens with nails. If properly installed, you will never damage the material, as the screwing of the screw is more smooth, and A pointed tip sets the direction, using a nail can split a wooden surface, accidentally hitting between fibers. Wood screws come in different sizes, depending on the thickness of the elements being joined, but they will all have distinctive features: a secret or semicircular head with a cross-shaped slot, a rare pitch of thread and sharp tip. Basically, for attaching wooden elements, use black or yellow screws. Choose such a length of the screw, so that when twisting the two elements, the thread enters the secondnot less than, than on¼ of thethickness of wood, then your mount will be reliable and able to withstand loads.
• For drywall.Drywall can be attached either to special metal profiles or to a wooden frame, depending on the material, there will be differences and self-cutting screws necessary for installation. To fasten to metal profiles, you should choose a screw with a frequent thread pitch and a drill bit on the end, then you do not have to pre-drill, which will significantly shorten the time installation. For fastening to a tree, choose a screw with a rare thread pitch and a sharp end. Before tightening, insert the sharp end into the gypsum board approximately to a depth of 1 mm. Whichever method of installation you choose, self-cutters for drywall will have common features:black color, which speaks of corrosion resistance due to the oxide or phosphate coating,countersunk head, which should be buried 1 mm into the sheet,cross-slot, so you can spin the screw not only with a screwdriver, but also with a screwdriver.
• For metal profiles and sheet metal.Self-tapping screws for metalacuteordrilltip and head in the formpress washers, which increases the contact area and provides a more dense pressing of the sheet elements to each other.Benefits of a drillThe tip consists in the absence of the need for pre-drilling, self-tapping screws and so on.easily screwedin the solid surface of the metal, eliminating the formation of chips or scratches. Self-tapping screws with a drill tip are very strong and can withstand heavy loads, and also have anti-corrosion properties. The thread pitch of such fasteners is rare, which makes it possible to dispense with the use of special bits or drills. Self-tapping screwsacutetippedThey have a frequent pitch of the thread, which allows the materials of different density to be well bonded. They are used mainly for fastening wood to metal, up to 2 mm thick. They also have anticorrosive properties and high strength. Self-tapping with a drill bit andhexagonalhead or self-cutters with a truncated cone ("fleas") And a drill bit. "Blocks" are used for a metal thickness of not more than 2 mm. Hexagonal screws are very convenient to twist with a key. Tochoose the correct lengthit is necessary to know the thickness of the part that you want to attach to the base andaddto this thickness10 mm. Since for reliability and strength of fasteners, the screw must enter the basement to a depth of at least 10 mm. The thread diameter of the self-tapping screw is 3.5 - 5.0 mm in 0.5 mm increments.
• For the window profile.A separate category of screws is for plastic windows, as such, not, but very often it is necessary to attach the same profile for slopes, or the same handle. Manufacturers of plastic windows, in addition to various accessories, put galvanized screws with countersunk head and sharp end. But from practice, this type of screws is not the most convenient - the sharp end slides, scrakes at the same time plastic, or even scrolls after installation, so experienced installers are advised to use self-tapping screwswith a drill bit at the end. They do not lead away when twisting, the window frame does not deteriorate and they are much more easily screwed. The size of the screws is determined by the thickness of what you want to screw to the window. For example, if it is a plastic, thin profile for future slopes, it is better to use small "fleas"With a drill at the end and a head in the form of a press washer, if the handle is with a hidden head with a cross-shaped spline. For reliable fastening, no more than 2-3 mm threading in the window profile is sufficient.
• On concrete.In order to screw something to concrete or brick, it is necessary to take into account that during installation the screw will be subjected to very heavy loads. For concrete work, choose a screwmade of galvanized steelwith a sharp end andcruciformorsix-pointedslot. The thread diameter should be not less than 7.5 mm, the possible length of self-tapping screws for concrete - 50-200 mm. If the base is loose, then you can do without pre-drilling, with a solid base you need to make a preliminary deep hole.
• For corrugated board.To fix metal and metal profiles, choosegalvanizedself-tapping screws visually similar to screws. The head of such screws hashexagonalshape, covered with polymer material of various colors, which allows you to choose a self-tapping screw in one color with a metal tile. Also included with these self-tapping screws is a neoprenewasherwith a rubber gasket that fits snugly against the roof and prevents moisture from entering the hole. The diameter of such screws is from 4.8 to 6.3 mm, and the length is from 190 to 250 mm.

4. How to choose the "right" self-tapping screw

It is not enough to decide on the kind of self-tapping that is necessary for a certain type of work, it is also necessary among a variety of optionschoosereallyquality, strong fasteners, which will not fail at the most crucial moment. Just carefully inspect the screw. It must correspond to suchsimple criteria:

• Same color gamut. All the screws of one batch must be the same color and shade, if it is a question of black or yellow screws. If all the products are in the same color, this may indicate that the whole batch has passed the same The type of treatment under the same conditions and has the same strength and corrosion firmness.
• Dimensionsself-cutters of one party should not visually differ from each other.
• Stepbetween turnscarvingmust be the same.
• If it is self-tapping with a drill bit on the end, then it should not have burrs on the edges, the sharp end of the screw must bewithout burrsand not be broken off.
• Hole, in the form of which the slot is made, shouldbe clear, symmetric and sufficientprofound.
• Qualitative self-tapping screws, usually, havemarkingin the form of a capital Latin letter. This indicates factory production, and this is a little hint in case you have to buy the missing fasteners.

If you see that the self-tapping screws you have chosen meet the above criteria, you can be Are sure that you are holding really high-quality fasteners that will not break in the process installation.

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