Anchor bolts can be installed in any wall: concrete, brick, etc. To attach such a bolt, you will need to clear the hole. The diameter of the hole should usually match the diameter of the bolt itself. In your case, when the diameter of the anchor is 10 millimeters, you need to drill a hole with a no smaller diameter. In this case, a 10 mm drill will do.
But one nuance should be taken into account. To accurately determine which drill to take, you will need to use a caliper to measure the actual diameter of the anchor bolt along with the thread. Sometimes it happens that the marking indicates one value, for example, 10 mm, but in reality the diameter of the bolt along with the thread differs by 1 millimeter. And that means the hole should be a little larger.
If you don’t have a caliper, you can use this method: use a thread to measure the circumference of the bolt, and then use the formula - Circumference (length) = 3.14 * diameter - to calculate the diameter value. That is, to calculate the diameter, you need to divide the resulting circle (its length) by 3.14.
The main thing when installing an anchor bolt is to avoid its deformation. If you can’t insert the anchor normally, then you need to check the hole: its diameter, the presence of debris, etc.
Anchor bolts can be installed in any wall: concrete, brick, etc. To attach such a bolt, you will need to clear the hole. The diameter of the hole should usually match the diameter of the bolt itself. In your case, when the diameter of the anchor is 10 millimeters, you need to drill a hole with a no smaller diameter. In this case, a 10 mm drill will do.
But one nuance should be taken into account. To accurately determine which drill to take, you will need to use a caliper to measure the actual diameter of the anchor bolt along with the thread. Sometimes it happens that the marking indicates one value, for example, 10 mm, but in reality the diameter of the bolt along with the thread differs by 1 millimeter. And that means the hole should be a little larger.
Basic selection principles
The correct choice of drill for the dowel should be based on the following:
- When calculating which hole to drill for the dowel, it is worth considering the type of wall into which the rod is installed and what it is covered with.
- Weight of attached furniture and maximum possible loads.
Considering the above parameters, you can choose the appropriate tool correctly. To make it easier, you need to take into account the factory size of the drill and fasteners, as well as the tensile strength of the dowel. There are markings on the tool, based on which it is easy to select the desired model.
If the wall material is very strong, for example concrete, you should choose two types of drills and different operating modes of the drill. To begin with, you should take a drill several sizes smaller than the dowels, switch the drill to impact mode and make the necessary hole. Then, using a gimlet of identical size with fasteners, in normal mode, bring the hole to the required parameters.
With the help of such manipulations, you can carry out work faster, do not overload the drill, get an ideally shaped hole and maintain the integrity of the wall and its coating. The rod in the hole should not rotate and move freely in it. Instead of a drill, it is better to choose a hammer drill, as it is more powerful and productive.
If the wall material is loose, it is better that the drill size is several sizes smaller than the rod (for example, for an 8 dowel, a drill size 6 or 7). This will allow the fasteners to be installed tightly, even in the event of excessive destruction of the wall structure.
When choosing the type of drill, you should pay attention to pobedit ones, given their high strength and durability.
The length of the hole should be several millimeters longer than the length of the dowel. This is necessary to ensure that it fits tightly into the niche over its entire length, since dust can accumulate in the hole.
What to consider when choosing a drill for a dowel
Selecting a drill to create a hole in which the dowel will be fixed should take into account:
- the material from which the wall itself is made, as well as its finishing;
- expected loads of the fastener.
You should also choose a drill depending on the diameter of the fasteners used. On the outer surface of factory-produced dowels, as a rule, there are markings that allow you to correctly select drills of the appropriate diameter for them.
Table 1. Selection of drill and screw for dowel
It is important to know not only how to choose a drill for a dowel, but also how to drill a hole correctly. If it is necessary to drill a hole in the wall for a dowel, the diameter of which is 10 mm, then first use a drill with a diameter of 8 mm and an impact drilling mode. After the hole is drilled, the tool is replaced with a drill with a diameter of 10 mm and is used without using the impact drilling mode. This approach will allow you to get a hole in the wall of the required diameter with smooth and neat edges.
If you need to drill a concrete wall, it is better to use a Pobedit drill, which can handle such a durable material without any problems. The selected cutting tool must be at least 3 mm longer than the dowel itself. If you neglect this requirement, the dowel will not completely fit into the resulting hole, in the final part of which dust and pieces of crumbled material, as a rule, accumulate. In addition, the shape of the bottom of the hole may not match the shape of the tip of the fastener.
Calculate the drilling depth with a margin relative to the dowel length
Types of dowels
Dowel type Driva
Perhaps the most popular fastener for plasterboard sheets. It comes with or without a drill, metal or plastic. When making a hole for its fastening, use a drill with a diameter of 8 mm. The manufacturer declares the working shear load that gypsum board can withstand using this dowel is 25 kg, while the maximum load is up to 50 kg.
The popularity of the Driva dowel is due to its fairly high reliability and relatively low price. The strength of such fastening is achieved by distributing the load over a large area, which is ensured by the shape of the dowel.
Driva drywall dowel is simple and effective
Flat dowel nail
This dowel is made of fire-resistant steel, is quite simple and easy to use, since it does not require additional drilling and, accordingly, eliminates dust. It can be hammered into the drywall with a hammer or pressed in by hand if you can do it.
The principle of operation of a dowel-nail is that when a self-tapping screw is screwed into it, the initially flat front part opens up, forming a reliable stop.
It is used for sheets up to 12.5 mm thick inclusive. Self-tapping screws are chosen with a diameter of 3.5-5mm. The working load for pulling out, declared by the manufacturer, is 15 kg, for shearing - 30 kg, the maximum shear load, obtained experimentally, is 48 kg. Among other things, the dowel-nail is reusable, that is, it can be dismantled and mounted in another place several times.
The flat dowel-nail for drywall is very convenient to install, as it does not require drilling
Universal expansion dowel Butterfly
The butterfly dowel is suitable for both drywall and concrete bases. The hole for its installation is drilled with a drill with a diameter of 8 mm, the diameter of the complete self-tapping screw is 4.5 mm.
For the butterfly dowel, we recommend using self-tapping screws without missing threads, since when screwing in, having reached the smooth neck, the self-tapping screw will begin to scroll, and the dowel will not take the desired shape as a stop.
In general, the plastic butterfly dowel works approximately the same as the others, creating a stop behind the gypsum board when screwing in the self-tapping screw. The shape of this stop is somewhat reminiscent of a butterfly, hence the name of the fastening element. The calculated working load on the dowel is 25 kg, the maximum load is 55 kg.
The Butterfly dowel for drywall is the most popular because it is equally inexpensive, convenient and effective.
Dowel Molly
The Molly dowel, or rather the Molly anchor (after all, it is an independent fastening unit that does not require an additional screw) is another popular type of fastening for drywall, made of metal. This dowel, unlike the previous ones, is available in various sizes and, accordingly, for various loads.
For example, for Molly of the minimum size marked 4/16/38 (4 is the diameter of the screw, 16 is the length of the neck and the maximum thickness of the sheet for which it can be used, 38 is the total length of the element), the working load is 25 kg, the limit for cutting is 47kg.
To make holes for Molly, choose a drill 2 times larger than the diameter of the neck (the first number in the marking), that is, for a four it will be 8 mm, for a six it will be 12, etc.
To install the Molly dowel, you need a special tool that brings the fastening element into “combat readiness”. With its help, the screw is slightly pulled towards itself, while the hooks bend. Then you can turn the screw with a screwdriver, bending the hooks until they stop. All this should be done by inserting a dowel into a hole in the drywall.
If there is no special tool, you can activate the anchor using wire cutters (side cutters) or even a regular flat-head screwdriver.
Molly dowel for drywall - a solution for professionals
Fischer plastic twist dowel
When a self-tapping screw is screwed into such a dowel, the latter twists, forming a stop behind a sheet of drywall, hence the name of the fastening element. The drilling diameter for such a dowel is 8 mm, the screw diameter is 5 mm.
When tightening a self-tapping screw, the main task is not to pinch too hard, otherwise it will begin to rotate and the fastener will need to be re-done. For this reason, when using a screwdriver for tightening, set it to the minimum speed.
The working load for tearing off a twisting dowel is 10 kg, for shearing - 25 kg, crash load - 70 kg.
Twistable plastic dowel for drywall - an interesting and effective solution, backed by Fisher reliability
How to fasten light weight objects
In order to fasten objects that are light in weight, use a quick mounting dowel. It is usually used for fastening lightweight objects to building structures made of brick and reinforced concrete.
As a rule, to solve this problem, a dowel is selected, the diameter of which, like the transverse size of the drill, is 6 mm. In this case, the length of the fastening element depends on the thickness of the wall of the object being fixed with it. If you need to select a dowel for mounting on the wall, then its length should be at least 4 cm, but if the mounting is on the ceiling, you need fasteners at least 6 cm long.
How to properly secure an anchor bolt?
To attach such an anchor bolt
in the wall it is installed in a hole drilled in the base material.
After this, you need to hit the rod hard with a hammer. When hammered, it wedges the bushing, providing reliable fixation.
A stud with a nut or
a bolt
into the fixed anchor .
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Bolt Load Calculation
The bolt head markings usually contain the following information:
- manufacturer's mark (JX, THE, L, WT, etc.);
- strength class;
- arrow “counterclockwise” (if left-hand thread).
The first digit indicates the nominal tensile strength (tensile strength): 1/100 MPa (1/100 N/mm²;
1/10 kg/mm²). Example: (strength class 9.8) 9*10=900 MPa (900 N/mm²; 91.71 kg/mm²).
The second number indicates the percentage of yield strength to tensile strength (tensile strength): 1/10%. Example: (strength class 9.8) 9*8=720 MPa (720 N/mm²; 73.37 kg/mm²).
The yield strength value is the maximum permissible working load of the bolt, above which irreversible deformation occurs. When calculating the load, 1/2 or 1/3 of the yield strength is used, with a double or triple safety margin, respectively.
According to the current international classification, high-strength bolts include products whose tensile strength is greater than or equal to 800 MPa (800 N/mm²; 81.52 kg/mm²). Accordingly, starting from 8.8 for bolts and 8 for nuts.
Examples of material flow
An example would be a common kitchen fork. By bending it in one direction, you can get a completely different object, which means its fluidity is disrupted, which leads to deformation. In this case, the material only deformed, but did not break, which indicates a high degree of elasticity of the steel. Conclusion: maximum strength is much higher than yield.
Other kitchen equipment, such as a knife, will break if you try to change its shape. Conclusion: the knife has the same fluidity and strength; such a product can be called fragile, despite the fact that it is made of steel.
A similar practical example would be screwing in a nut: the bolt itself increases in length only after a certain amount of action is applied to it. If the outcome of the experiment is unfavorable, the thread on the fastener may break.
The percentage of elongation is an average indicator that demonstrates the length of the deformed part before the onset of failure. Figuratively, we can call this kind of bolts flexible, meaning precisely the ability to elongate.
The technical terminology for this is quite simple: elongation is nothing more than the percentage of increase in a sample compared to its original size.
Material hardness
Brinell hardness is a characteristic that allows you to determine the hardness of a material.
Stainless steel fasteners are also equipped with special markings on the top of the fastener.
Type of steel A2 or A4 and tensile strength - 50, 70, 80, examples: A2-70, A4-80. Fasteners that have a clearly defined thread are color-coded for A2 in green and for A4 in red. The value for the yield strength is not specified.
For example, a value of 70 is the most standard and demonstrates the maximum strength of stainless steel fasteners.
Maximum fluidity for stainless steel hardware, often only a reference value.
The fluidity in this case will be 250 N/mm2 for A2-70 and about 300 N/mm2 for A4-80.
The approximate increase will be no more than 40%. In other words, this type of steel perfectly changes shape before irreparable deformation occurs.
Old domestic measurement methods according to GOST did not allow paying due attention to the maximum permissible loads on bolts, so the produced hardware was significantly lower in quality compared to modern ones.
An example to calculate the load on a material as accurately as possible using strength classification:
M12 fastening with strength 8.8, size d2 = 10.7 mm and maximum section length 89.87 mm2. In this case, the maximum permissible degree of load will be: (8*8*10)*89.87;0) = 57520 Newton.
Load chart for carbon steel and stainless steel bolts.
| ST-4.6 | ST-8.8 | A2-70 | A4-80 | |||||||
| THREAD | d2, mm | Area 62, tt2 | Max. load, Newton | Working load, kg | Max. load, Newton | Working load, kg | Max. load, Newton | Working load, kg | Max. load, Newton | Working load, kg |
| M1 | 0,8 | 0,5 | 121 | 322 | 10 | 126 | 151 | |||
| M2 | 1,7 | 2,27 | 544 | 20 | 1 452 | 70 | 567 | 20 | 681 | 30 |
| M3 | 2,6 | 5,31 | 1 274 | 60 | 3 396 | 160 | 1 327 | 60 | 1 592 | 70 |
| M4 | 3,5 | 9,62 | 2 308 | 110 | 6 154 | 300 | 2 404 | 120 | 2 885 | 140 |
| M5 | 4,4 | 15,2 | 3 647 | 180 | 9 726 | 480 | 3 799 | 180 | 4 559 | 220 |
| M6 | 5,3 | 22,05 | 5 292 | 260 | 14 112 | 700 | 5 513 | 270 | 6 615 | 330 |
| M8 | 7,1 | 39,57 | 9 497 | 470 | 25 326 | 1 260 | 9 893 | 490 | 11 872 | 590 |
| M10 | 8,9 | 62,18 | 14 923 | 740 | 39 795 | 1 980 | 15 545 | 770 | 18 654 | 930 |
| M12 | 10,7 | 89,87 | 21 570 | 1 070 | 57 520 | 2 870 | 22 469 | 1 120 | 26 962 | 1 340 |
| M14 | 12,6 | 124,63 | 29 910 | 1 490 | 79 761 | 3 980 | 31 157 | 1 550 | 37 388 | 1 860 |
| M16 | 14,6 | 167,33 | 40159 | 2 000 | 107 092 | 5 350 | 41 833 | 2 090 | 50199 | 2 500 |
| M20 | 18,3 | 262,89 | 63 093 | 3 150 | 168 249 | 8 410 | 65 722 | 3 280 | 78 867 | 3 940 |
| M24 | 21,9 | 376,49 | 90 359 | 4 510 | 240 956 | 12 040 | 94 123 | 4 700 | 112 948 | 5 640 |
| M27 | 24,9 | 486,71 | 116 810 | 5 840 | 311 493 | 15 570 | 121 677 | 6 080 | 146 012 | 7 300 |
| M30 | 27,6 | 597,98 | 143 516 | 7170 | 382 708 | 19130 | 149 495 | 7 470 | 179 394 | 8 960 |
We present to your attention an updated table of maximum loads on stainless materials and high-strength connections.
To be additionally confident in the safety of the load, you can, without a twinge of conscience, divide the load in Newtons by thirty.
| Stainless steel A2-50 | |||||||
| THREAD | d2, mm | Area d2, mm2 | Yield strength, MPa | Max. load, Newton | Working load, kg | ||
| M1 | 0,8 | 0,50 | 200 | 100 | |||
| M2 | 1.7 | 2,27 | 200 | 454 | 20 | ||
| M3 | 2,6 | 5,31 | 200 | 1 061 | 50 | ||
| M4 | 3,5 | 9,62 | 200 | 1 923 | 90 | ||
| M5 | 4,4 | 15,20 | 200 | 3 040 | 150 | ||
| MB | 5,3 | 22,05 | 200 | 4 410 | 220 | ||
| M8 | 7,1 | 39,57 | 200 | 7 914 | 390 | ||
| M10 | 8,9 | 62,18 | 200 | 12 436 | 620 | ||
| M12 | 10,7 | 89,87 | 200 | 17 975 | 890 | ||
| M14 | 12,6 | 124,63 | 200 | 24 925 | 1 240 | ||
| M16 | 14,6 | 167,33 | 200 | 33 466 | 1 670 | ||
| M20 | 18,3 | 262,89 | 200 | 52 578 | 2 620 | ||
| M24 | 21,9 | 376,49 | 200 | 75 299 | 3 760 | ||
| M27 | 24,9 | 486,71 | 200 | 97 342 | 4 860 | ||
| MLO | 27,6 | 597,98 | 200 | 119 596 | 5 970 | ||
| Stainless steel A2-70 | |||||||
| THREAD | 62.mm | Area d2, mm2 | Yield strength, MPa | Max. load, Newton | Working load, kg | ||
| M1 | 0,8 | 0,50 | 250 | 126 | |||
| M2 | 1,7 | 2,27 | 250 | 567 | 20 | ||
| M3 | 2,6 | 5,31 | 250 | 1 327 | 60 | ||
| M4 | 3,5 | 9,62 | 250 | 2 404 | 120 | ||
| M5 | 4,4 | 15,20 | 250 | 3 799 | 180 | ||
| MB | 5,3 | 22,05 | 250 | 5 513 | 270 | ||
| M8 | 7,1 | 39,57 | 250 | 9 893 | 490 | ||
| M10 | 8,9 | 62,18 | 250 | 15 545 | 770 | ||
| M12 | 10,7 | 89,87 | 250 | 22 469 | 1 120 | ||
| M14 | 12,6 | 124,63 | 250 | 31 157 | 1 550 | ||
| M16 | 14,6 | 167,33 | 250 | 41 833 | 2 090 | ||
| M20 | 18,3 | 262,89 | 250 | 65 722 | 3 280 | ||
| M24 | 21,9 | 376,49 | 250 | 94 123 | 4 700 | ||
| M27 | 24,9 | 486,71 | 250 | 121 677 | 6 080 | ||
| MLO | 27,6 | 597,98 | 250 | 149 495 | 7 470 | ||
| Stainless steel A4-80 | |||||||
| THREAD | 12, mm | Area d2, mm2 | Yield strength, MPa | Max. load, Newton | Working load, kg | ||
| M 1 | 0,8 | 0,50 | 300 | 151 | |||
| M2 | 1,7 | 2,27 | 300 | 681 | 30 | ||
| M3 | 2,6 | 5,31 | 300 | 1 592 | 70 | ||
| M 4 | 3,5 | 9,62 | 300 | 2 885 | 140 | ||
| M 5 | 4,4 | 15,20 | 300 | 4 559 | 220 | ||
| MB | 5,3 | 22,05 | 300 | 6 615 | 330 | ||
| M 8 | 7,1 | 39,57 | 300 | 11 872 | 590 | ||
| M10 | 8,9 | 62,18 | 300 | 18 654 | 930 | ||
| M12 | 10,7 | 89,87 | 300 | 26 962 | 1 340 | ||
| M14 | 12,6 | 124,63 | 300 | 37 388 | 1 860 | ||
| M16 | 14,6 | 167,33 | 300 | 50199 | 2 500 | ||
| M20 | 18,3 | 262,89 | 300 | 78 867 | 3 940 | ||
| M24 | 21,9 | 376,49 | 300 | 112 948 | 5 640 | ||
| M27 | 24,9 | 486,71 | 300 | 146 012 | 7 300 | ||
| MLO | 27,6 | 597,98 | 300 | 179 394 | 8 960 | ||
Calculation of anchors
Performing a pull-out test on connections is often performed on site. The permissible load will depend on the base material, for example:
When installing massive structures at height, the required tensile strength should be about 700 kg, which is why experts recommend using chemical types of anchors for such fastenings. When using concrete or brick as a base, the average load is about 350 kg, this value is sufficient for fastening medium and heavy structures. When using foamed concrete, the load it can withstand will be about 250 kg. In addition to calculating the load-bearing capacity of the elements used, the correct tightening torque of threaded connections must be ensured. If the tightening is insufficient, there may be no frictional force in the connection; if the recommended values are exceeded, there is a possibility of material destruction due to excess pressure on the base.
Fastening medium-weight products
Objects weighing between 5–10 kg are secured with impact dowels Ø8 mm, a drill Ø8 mm, but always with a Pobedit tip. The fastener should extend into the wall cavity by 6 cm, and if the ceiling is 8 cm. To secure an object weighing up to 10 kg, 4 fasteners should be used.
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