When carrying out repairs, self-tapping screws are indispensable consumable. With their help, you can fix any design on a specific surface. For reliable fixation of the self-tapping screw in the material, it is also necessary to use a dowel. The dowel is fixed at the base of the material, then a self-tapping screw is screwed into it. Dowels are plastic and metal. They always have a spacer in their design - an element that increases the adhesion of fasteners to the material.
Options for choosing a dowel for a self-tapping screw
For reliable fastening, you should choose the dowel for the self-tapping screw accurately and correctly. It is necessary to take into account the dimensions of the self-tapping screw and dowel, as well as the thickness of the fixed product. If the diameter of the self-tapping screw exceeds the diameter of the dowel, the self-tapping screw will break the dowel. If, on the contrary, the diameter of the dowel is larger than the diameter of the self-tapping screw, the spacers will not open completely and the fastening will not be strong enough. The same will happen if the self-tapping screw is shorter in length than the dowel used.
The choice of dowel must begin with its dimensional characteristics. Larger dowels are able to withstand heavy loads. Dowels of various diameters are designed for a certain load:
· 14 mm and above - very heavy load.
In addition to the dimensional characteristics, you need to know the density of the material in which the dowel is fixed. Dowels of the same size withstand greater loads in denser materials. Also, the dowel is selected by type, depending on the purpose of use and the structures to be fixed.
Types of dowels and screws for them
There are the following types of plastic and metal dowels:
· Spacer. These dowels are produced and used for fixing in concrete bases. The design of such a dowel provides for 2 or 3 spacers. Expansion dowels are used to fasten light parts. Such a dowel can be ideally fixed in a loose wall.
· Dowels of this type are made of metal, equipped with large threads and a special drill. This helps to avoid pre-drilling a hole before installation. Not designed for heavy loads.
· Dowel nail . Consists of a plastic dowel and a steel nail for increased strength. When driving in a nail, the dowel is firmly fixed in the material. This type used for fixing metal profiles and skirting boards.
· Anchor. These dowels are made of metal. They are shaped like a cylinder. A nut is located at the base of the cylinder. When tightening the self-tapping screw, the nut opens the spacers in the hole, which provides a strong fixation. Used for fixing massive components.
· Dowel-butterfly. Necessary for hanging large items. At the base, like the anchor dowel, there is a nut. When tightening the self-tapping screw, the nut presses on the spacers, which abut against the inner surface of the product. It is just as good for fixing in a loose wall as an expansion dowel.
· Dowel fungus. Dowels of this type are indispensable for thermal insulation work. With the help of them, the insulation is fixed on the surface of buildings.
After the choice desired type the dowel is made, it is necessary to select the corresponding self-tapping screw. With the help of a special table comparing the sizes of the dowel and the self-tapping screw, you can find out how to choose the dowel for the self-tapping screw.
|
|
|
Attachment material thickness (mm) |
Screw size (mm) |
For example, you have a dowel with a diameter of 10 mm and a length of 50 mm. The thickness of the fixed material in this case is 10 mm. To find out how to choose a dowel for a self-tapping screw of the right size, we turn to the table. With the given parameters, our dowel will fit a 6x60 self-tapping screw, as can be seen from the table. When fixing structures with minimum thickness material, a dowel for a self-tapping screw 3.5 mm x 25 mm is suitable.
Using the above material, you can easily pick up a dowel for a self-tapping screw and perform necessary work quality and professional.
A dowel-screw is a fastener used to fix various products in a solid base. The principle of operation is based on the friction force that occurs when a screw is screwed into the dowel.
Brief historical background
The name of the dowel's inventor and the date of its invention are unknown. But January 14, 1913 is the day the Englishman John Joseph Rawlings received a patent for this fastener.
The first devices of this kind were made of wood. Today, polyethylene, polypropylene and metal dowels are produced.
In addition, the use of nylon dowels is widespread - their use allows you to solve many problems. These fasteners complete with screws are appropriate to use when working with any material.
Description
Nowadays, none repair work cannot be imagined without the use of dowels. There is always something to attach to the wall or ceiling surface. Only if the walls and ceiling are made of wood, you can use nails and a hammer. In all other situations, dowel fasteners are indispensable.
There is a wide range of similar products on sale, differing from each other in the material of manufacture and the method of retention. In addition, the weight and size of the dowel-screws can be very different.
The mounting dowel can be not only polypropylene, but also nylon. The use of the former is possible only in interior decoration, since sub-zero temperatures contribute to the formation of cracks on them. And nylon fasteners are equally well suited for both indoor and outdoor use.
The expansion dowel is used when fastening structures to hollow blocks, concrete and brick. Fixation occurs with the help of special antennae. They securely hold the dowel and prevent it from turning. Exist certain types dowels designed for a construction gun. Despite the different installation method, they are quite effective.
The specifics of the dowel-screw
As you can see in the photo of the dowel-screw, it can be either with or without a locking collar. The dowel with a shoulder is usually made of nylon. It is used in outdoor installation work. The stoppers hold fasteners, preventing them from falling into the hole.
The fastener without collar is made of polyamide. His hallmarks are through hole, longitudinal ribs and non-expansive top. Such a design solution greatly simplifies screwing in, increasing the degree of expansion of the dowel.
And the fixed top protects the plastered surface from cracks. In addition, collarless fasteners are resistant to atmospheric precipitation and their service life is much longer.
- This is a specialized fastener used for mounting and fixing different designs to the walls of buildings. The most popular are dish type products.
The dowel-screw for drywall can be either plastic or metal. Its purpose is to fix products on plasterboard or gypsum fiber sheets and porous concrete.
Metal fasteners do not require pre-drilling holes - they have a feather drill at the end, and the spacers are threaded. Installation of such a dowel occurs with a screwdriver.
The principle of operation of a universal dowel-screw in a thick wall is similar to the principle of operation of a conventional spacer. If the wall is thin, then after passing it, the dowel is screwed onto the screw and tied into a knot, which makes the fastener as reliable as possible.
Scope of application of the mounting dowel-nail - quick installation double-glazed window, plinth, lathing, etc. The component is a nail, which has a knurled thread with a reverse cone for better fixation. For its installation and a screwdriver and a hammer.
The purpose of the adjusting dowel is to fix wood products during the internal arrangement of buildings. It allows you to do without the use of pads and wedges for leveling an uneven wall surface.
For mounting household appliances it is permissible to use the fasteners supplied with it. They are calculated with the required margin of safety. When choosing dowel-screws on your own, you must take into account the mass of the load and the material of the wall.
To fix a chandelier or suspended ceiling system, opt for special dowels equipped with deep transverse notches and spacer ribs.
Photo dowel-screws
Rabitz
Netting mesh produced by our factory can be made of black or galvanized wire up to 4 mm in diameter with mesh sizes from 20x20 to 90x90 mm. Roll height up to 3 meters. Metalware Plant No. 2 sells mesh netting wholesale and retail (delivery is possible). Chain link mesh production standard sizes to order. ZMI - 2 also produces mesh "RABITS" with pvc coated different colors (in stock and on order). All information about chain-link mesh: history, production, application
Our factory offers you untreated galvanized wire various diameters in any quantity. for more detailed information, please contact the central office by phone: +7 (495) 645-97-55
Chain link fence sections
Our factory produces fence sections from a corner, covered with a mesh - chain-link, gates and gates from a chain-link mesh. You can purchase such fence sections in both standard sizes and order sizes according to your individual requirements. In fact, you get a ready-made fence. No need to suffer with the installation and stretching of the grid. This fence will last longer!Welded fencing sections
Various types: You can choose one of the options offered by us or order the production of welded fencing sections from us according to your own sketches or drawings. Such fences are suitable everywhere: from fencing a front garden in a country house to restricting access to construction sites for unauthorized persons.
made from galvanized sheet metal thickness from 0.5 mm. up to 1.0 mm. method of simultaneous cutting and drawing.
self-tapping screws
Metalware Plant No. 2 offers various purposes and with different coating: oxidized, galvanized, yellow-pasted self-tapping screws. Self-tapping screws with frequent threads are used for fastening thin metal parts to plastic or wood. Self-tapping screws with coarse thread used for fastening wooden parts, insulation, fiberboard, etc.
Nails
Metalware Plant No. 2 manufactures and sells a variety of nails from the simplest construction to ruffed nails, including slate ruffed ones. The whole range of nails You can purchase at our retail outlets or in bulk through our office in Moscow.
Furnace casting
If you need cast iron products for furnaces who are commonly called , then it's up to us!
Cast iron is used to make both small collapsible stoves "potbelly stoves" for summer cottages and gardens, as well as individual parts and accessories for stoves.
Cast iron in conditions high temperatures strong enough, not subject to corrosion and deformation, durable.
Bolts and nuts
Other fasteners and hardware
Metalware Plant No. 2 offers a wide range of other fasteners and hardware, namely: bolts, nuts different sizes, washers, rivets. Our factory sells such rarely offered sale hardware, as a welded chain (without quality control), carabiners.
12.05.2015
Many are faced with the problem of selecting a dowel for a self-tapping screw, when it is necessary to fix any structure to concrete, brick, aerated concrete or drywall with a self-tapping screw, but in this case one cannot do without a dowel.
It is necessary to take into account the diameter and length of the self-tapping screw, and the diameter and length of the dowel, and the thickness of the material to be attached. If the dowel is less than the diameter set, then the self-tapping screw will break it, if more, then the self-tapping screw will not open it properly and there will be no reliable installation, the same will happen if the self-tapping screw does not reach the end of the dowel. But how, after all, is it right to choose a self-tapping screw and dowel?
You need to start the selection with the dowel, with its size (diameter, length). The larger the size of the dowel, the greater the load it can withstand. The smallest diameter is 4 mm and 5 mm for light loads, 6 mm and 8 mm for medium loads, 10 mm and 12 mm for heavy loads, 14 mm and 16 mm for very heavy loads, for fastening scaffolding etc. You should also take into account the density of the material in which the dowel will be located. The denser the material, the greater the load that the dowel of the same size can withstand.
After we have selected right size dowel, you can pick up a self-tapping screw to it.
For a dowel with a diameter of 4 mm, a self-tapping screw with a diameter of 2 mm is suitable.
For a dowel with a diameter of 5 mm, a self-tapping screw with a diameter of 2.5 mm is suitable. (from 2 mm to 3 mm.)
For a dowel with a diameter of 6 mm, a self-tapping screw with a diameter of 4 mm is suitable. (from 3.5 mm to 4.5 mm)
For a dowel with a diameter of 8 mm, a self-tapping screw with a diameter of 5 mm is suitable. (from 4.5 mm to 5.5 mm)
For a dowel with a diameter of 10 mm, a self-tapping screw with a diameter of 6 mm is suitable. (from 5.5 mm to 6.5 mm)
For a dowel with a diameter of 12 mm, a self-tapping screw with a diameter of 8 mm is suitable. (from 6.5 mm to 8.5 mm)
For a dowel with a diameter of 14 mm, a self-tapping screw with a diameter of 10 mm is suitable. (from 8.5 mm to 10.5 mm)
For a dowel with a diameter of 16 mm, a self-tapping screw with a diameter of 12 mm is suitable. (from 10.5 mm to 12.5 mm)
Well, we have selected the desired size of the dowel, selected the required diameter of the self-tapping screw for it, now it only remains to select the desired length of the self-tapping screw.
For this, the length of our dowel is taken, the thickness of the attached material is added, and we get the required minimum length of the self-tapping screw. The thickness of the fastened material should not be more than 35% in loose bases, and not more than 60% in dense bases of the length of the dowel.
The self-tapping screw can come out of the dowel a little, it's not scary, the main thing is that it must go to the end of the dowel and completely open it, for reliable installation, if it is not screwed in completely, then the dowel can turn, and the installation will not be reliable. You need to drill a hole for the dowel a little more than its length and the same diameter.
For example: we need to fasten 20mm thick plywood to concrete floor. To do this, we take an 8x50 dowel (8 mm dowel diameter, 50 mm length), and a 5x70 self-tapping screw (5 mm self-tapping screw diameter, 70 mm length) to it. For drilling, we need a drill 8x110 (8 mm diameter, 110 mm total length of the drill, 80 mm length of the working part). You need to drill to a depth of at least 60 mm. After drilling, the hole is cleaned of dust, a dowel is inserted, then a self-tapping screw is screwed into it through plywood.
Correspondence table for self-tapping screws and dowels
|
Dowel diameter (mm.) |
Dowel length (mm.) |
Thickness of attached material (mm.) | Screw size (mm.) |
| 5 | 25 | 5 | 3x30 |
| 5 | 25 | 10 | 3x35 |
| 6 | 25 | 5 | 4x30 |
| 6 | 30 | 5 | 4x35 |
| 6 | 30 | 10 | 4x40 |
| 6 | 35 | 10 | 4x45 |
| 6 | 35 | 15 | 4x50 |
| 6 | 40 | 10 | 4x50 |
| 6 | 40 | 15 | 4x60 |
| 6 | 40 | 20 | 4x60 |
| 6 | 50 | 10 | 4x60 |
| 6 | 50 | 15 | 4x70 |
| 6 | 50 | 20 | 4x70 |
| 8 | 30 | 5 | 5x35 |
| 8 | 30 | 10 | 5x40 |
| 8 | 40 | 10 | 5x50 |
| 8 | 40 | 15 | 5x60 |
| 8 | 50 | 10 | 5x60 |
| 8 | 50 | 20 | 5x70 |
| 8 | 60 | 10 | 5x70 |
| 8 | 60 | 20 | 5x80 |
| 8 | 60 | 30 | 5x90 |
| 8 | 80 | 10 | 5x90 |
| 8 | 80 | 20 | 5x100 |
| 8 | 80 | 30 | 5x120 |
| 10 | 50 | 10 | 6x60 |
| 10 | 50 | 20 | 6x70 |
| 10 | 60 | 20 | 6x80 |
| 10 | 60 | 30 | 6x90 |
| 10 | 80 | 20 | 6x100 |
| 10 | 80 | 40 | 6x120 |
| 10 | 80 | 60 | 6x140 |
| 10 | 100 | 40 | 6x140 |
| 10 | 100 | 50 | 6x150 |
| 10 | 100 | 60 | 6x160 |
| 12 | 70 | 10 | 8x80 |
| 12 | 70 | 20 | 8x90 |
| 12 | 70 | 30 | 8x100 |
| 12 | 100 | 20 | 8x120 |
| 12 | 100 | 40 | 8x140 |
| 12 | 100 | 60 | 8x160 |
| 12 | 120 | 40 | 8x160 |
| 12 | 120 | 60 | 8x180 |
| 12 | 120 | 80 | 8x200 |
| 14 | 75 | 25 | 10x100 |
| 14 | 75 | 35 | 10x120 |
| 14 | 100 | 20 | 10x120 |
| 14 | 100 | 40 | 10x140 |
| 14 | 100 | 60 | 10x160 |
| 14 | 135 | 25 | 10x160 |
| 14 | 135 | 35 | 10x180 |
| 14 | 135 | 45 | 10x180 |
In this article, we showed you how to choose the right screws for the dowel. If you still have questions, please contact our online store KREP-KOMP, on the phone, e-mail skype. Our managers will be happy to advise you on all issues!
Dowel- an auxiliary element for fasteners, providing reliable adhesion of self-tapping screws or screws to the supporting base.
Dowels are made of plastic (polypropylene, polyethylene, nylon) and metal (iron, stainless steel, brass). The dowel can be conditionally divided into two parts. Spacer (in the photo below, the left side of the dowel), it is responsible for the force of holding the self-tapping screw in the material, and non-expandable (in the photo below, the right side of the dowel). The non-expansion part of the dowel is needed in order not to destroy the soft layer of materials. For example, you install a dowel in a plastered brick wall, if there is no non-expandable part, then when you twist the self-tapping screw around the dowel, the plaster will collapse. you hang wall cabinet behind the base through the chipboard, then the length of the spacer should be equal to the thickness of the chipboard plus the size of the plaster layer, it turns out about 30 mm.
The non-expansion part of the dowel may have a countersunk, cylindrical or round flange. The flange does not allow the dowel to sink into the hole of the material to be fixed or into the wall. The use of dowels with a flange is convenient if the flange does not interfere.
When screwing the self-tapping screw, the expansion part of the dowel, which has an inner diameter much smaller than the diameter of the dowel, tries to move apart, but the wall material interferes and the plastic of the dowel is compacted under high pressure, connecting the self-tapping screw with the wall into one whole.
Dowels for fixing products on a plasterboard wall
For fixing objects on plasterboard walls, a special dowel is designed, the end of which is equipped with cutting edges that act as a drill. To install such a dowel in plasterboard wall it does not require pre-drilling a hole, which allows you to fix the object on the wall in the absence of a drill and a drill.
After installation, a self-tapping screw is screwed into the dowel without changing the geometry of the dowel. The dowel can be easily unscrewed from drywall and reused.
There is another special dowel for attaching products to a drywall wall called Molly (Molly). Its builders call it "Butterfly", because when screwing in a self-tapping screw, the expansion part of the dowel diverges to the sides behind inside drywall, taking the form of butterfly wings. This is due to the fact that at the end of the expansion part there is a thickening into which the self-tapping screw is screwed, folding the expansion part of the dowel in half, firmly fixing the dowel in the plasterboard.
Such a dowel allows you to fix a product weighing up to 10 kg on drywall. Here is an example of fastening with a Butterfly-type dowel large mirror on a plasterboard wall.
Choosing a dowel for a self-tapping screw
After the choice of the type of self-tapping screw and dowel for wall mounting is made, it remains to choose, using the data given in the table below, the size of the self-tapping screw and the corresponding dowel. Decide on the diameter and depth of the hole for installing the dowel.
Due to the lack of an international standard for self-tapping screws and dowels, many manufacturers produce according to their own internal standards. Therefore, it is impossible to accurately indicate all dimensions, but in the vast majority of cases, the dimensions coincide with sufficient for practical use accuracy.
| Dowel selection table for the selected self-tapping screw, hole size for the selected dowel | |||||
|---|---|---|---|---|---|
| self-tapping screw | Dowel | dowel hole | |||
| Diameter, mm | Length, mm | Diameter, mm | Length, mm | Drill diameter, mm | Drilling depth, mm |
| 3 | 12, 16, 20, 25, 30, 35, 40 | 5 | 12, 16, 20, 25, 30, 35, 40 | 5 | 16, 20, 25, 30, 35, 40, 45 |
| 3,5 | 6 | 12, 16, 20, 25, 30, 35, 40, 45, 50 | 6 | 16, 20, 25, 30, 35, 40, 45, 50, 55 | |
| 4 | 5 or 6 | 12, 16, 20, 25, 30, 35, 40, 45, 50, 60, 70 | 5 or 6 | 16, 20, 25, 30, 35, 40, 45, 50, 55, 65, 75 | |
| 4,5 | 6 or 8 | 16, 20, 25, 30, 35, 40, 45, 50, 60, 70, 80 | 6 or 8 | 20, 25, 30, 35, 40, 45, 50, 55, 65, 75, 85 | |
| 5 | 20, 25, 30, 35, 40, 45, 50, 60, 70, 80, 90, 100 | 6 or 8 | 16, 20, 25, 30, 35, 40, 45, 50, 60, 70, 80, 90, 100 | 6 or 8 | 20, 25, 30, 35, 40, 45, 50, 55, 65, 75, 85, 95, 105 |
| 6 | 8 or 10 | 40, 45, 50, 60, 70, 80, 90, 100, 120, 140, 160, 180, 200 | 8 or 10 | ||
| 8 | 40, 45, 50, 60, 70, 80, 90, 100, 120, 140, 160, 180, 200 | 10 or 12 or 14 | 40, 45, 50, 60, 70, 80, 90, 100, 120, 140, 160, 180, 200 | 10 or 12 or 14 | 45, 50, 55, 65, 75, 85, 95, 105, 130, 150, 170, 190, 220 |
| 10 | 12 or 14 | 40, 45, 50, 60, 70, 80, 90, 100, 120, 140, 160, 180, 200, 220, 240, 260 | 12 or 14 | 45, 50, 55, 65, 75, 85, 95, 105, 130, 150, 170, 190, 220, 230, 260, 280 | |
The table should be used as follows. Suppose you need to hang bookshelf with a maximum possible weight of 100 kg with fastening on two loops on brick wall. Since the shelf will be suspended on two self-tapping screws, the load on one self-tapping screw will be 50 kg. Choose from the table, a self-tapping screw with a universal thread, with a hemispherical head, with a diameter of 6 mm, a length of at least 80 mm. The dowel is suitable standard, the simplest. From the table we see that there is such a standard size of a self-tapping screw; a dowel with a diameter of 8 or 10 mm and a length of 80 mm is suitable for it. Since there is a drill with a diameter of 8 mm, we also choose a dowel with a diameter of 8 mm. To install it, you need to drill a hole with a diameter of 8 mm to a depth of 85 mm.
Making a dowel from improvised material
As a dowel, you can successfully use a furniture dowel. It is made from hard rock wood. Diameter 8 mm, length 40 mm, with longitudinal ribs. Previously, in the manufacture of furniture, fastening with dowels was widespread.
Sometimes there is a need to urgently fix an object on the wall, but there is no ready-made factory-made dowel at hand. In this case, you can independently plan it out of any dry piece of wood. A leg from a chair or stool will do. This has always been done before, for the reason that there were no plastic dowels on sale. With a homemade dowel, it is advisable to chamfer on one side, so that it is easier to hammer into the wall.
In order to screw a self-tapping screw into a wooden dowel, it is necessary, after driving it into the wall, to drill a hole in its center with a diameter slightly less than the diameter of the threaded part of the self-tapping screw.
A good dowel can be made from a television cable, in which the central core is insulated from the braid with polypropylene, cutting off a piece of the required length from it. To do this, remove the outer insulation and shielding braid, remove the central core. Next, cut the cut piece of insulation in half to a third of its length. In the uncut part, drill a hole equal to the diameter of the self-tapping screw. On the outside dowels, it is desirable to make notches with a soldering iron so that the dowel does not rotate in the wall when the self-tapping screw is tightened.
You get a dowel, no worse than an industrial design. True, there is a lot of fuss, but if you only need a few, then it makes sense to make it yourself.
Sometimes unexpected things happen when drilling a hole in a wall. The drill, due to the heterogeneity of the wall material or if it fails to hit the joint of bricks, drills a hole not very accurately, and even much bigger size than a dowel. The dowel dangles, and in this case there will be no self-tapping screw to hold in the wall. Sometimes the wall is very loose and a large piece of it breaks off. But there is a simple solution that I have been using since time immemorial.
An aluminum or copper wire is wound onto the self-tapping screw, with a diameter equal to the thread pitch of the self-tapping screw or screw. It turns out a metal dowel with a thread. Since I came across a dowel with a double thread, I wound the wire in two passes. In such a wire dowel, the self-tapping screw is easily twisted and unscrewed. To prevent the wire dowel from turning in the wall, you should make edges on it with a file with a file.
The dowel is mounted in the wall as follows. A solution of cement, alabaster, gypsum or other similar is diluted mortar, the drilled hole is filled and a wire dowel is inserted with a self-tapping screw screwed into it until it is drowned in this solution. If it is hard to insert, you can tap with a hammer. After the mortar has hardened, the self-tapping screw can be unscrewed and the desired item can be hung on the wall. It will hold securely.
Sometimes it happens that a hole drilled in the wall with a drill of a given diameter does not provide a tight fit for the dowel, and when screwing the self-tapping screw into the dowel, it turns. In this case, you can use the composition "Liquid nails". From the tube, the drilled hole in the wall is completely filled with mortar and the dowel is immediately inserted into it. After half an hour, it will be possible to safely twist a self-tapping screw into the dowel. Will hold tight.
With the help of liquid nails, according to the technology described above, it is also possible to securely fix a standard plastic dowel in a wall lined with porous material, such as foam concrete.
There are times when the dowel cannot be completely driven into the hole, and it protrudes a little, but cannot be removed. The protruding part must be removed. It can be cut with a hacksaw blade for metal.
To exclude damage to the wall covering, it is enough to take a small sheet of sandpaper, make a hole in it with a diameter equal to the diameter of the dowel, put it on the dowel with the emery side to the wall and carefully cut it off. The wall covering will remain intact.