For reliable and high-quality fastening of 2 or more parts to each other, it is fundamentally important to select the correct dimensions of the fastening elements. This question often causes difficulties, because even the sizes of wrenches are selected taking into account the sizes of the fasteners themselves. Therefore, we will consider all the nuances that are important to consider when choosing the necessary hardware.
The main parameters by which bolts and nuts are selected are the diameter of the product, its thickness and length. But besides them, there is a number of important data, information about which is printed on the hardware. This:
- metric thread (it is designated as M);
- thread pitch (it can be especially small, small, large, especially large, in the latter case the value is not added, denoted as P);
- diameter of the product (designation – D);
- product length (denoted L).
The numbers next to the letter designation of the parameters are data indicated in millimeters. To find out the type, as well as correctly determine the size of, for example, a bolt, you must first find out what type of fastener is needed. Here it is permissible to use domestic GOST, European ISO quality standards or even DIN standards (Germany).
Bolt and nut sizes
All mechanisms in structural elements have certain types of bolted connections. Information on the connection is indicated by the manufacturer in the technical and also accompanying documentation. However, consumers may not always have access to such documentation, due to many factors. How then? In this case, you can quickly and accurately determine the dimensions of bolts and nuts:
- The size of a nut or hex bolt is determined by measuring the distance between two parallel edges. The diameter of the threaded part can be found without measuring with a ruler or caliper in the technical information for the fastening element. The marking on the hardware is indicated by the letter D.
- If you have a sample, you should examine it carefully. Often markings are indicated not only in the documentation, but also on the surface of the product. This simplifies the process of selecting fasteners. However, it happens that the bolts are damaged and the information indicated on the head is not readable.
- You can contact specialists who will instantly select a new fastener of the required size based on the sample. And they will offer bolts in bulk, the price and quality of which will meet all your requirements.
- Take measurements yourself. Note that the key characteristics are the overall dimensions, as well as the thread pitch and bolt diameters. It is necessary to know the basic technical parameters of bolts, since this will allow you to correctly determine the choice of tool size.
- You can use a caliper to measure the size of the head. It allows you to accurately determine the distance that is formed between the edges of the cap. When measuring, the obtained values should be transferred to a millimeter tape.
- When determining turnkey dimensions, attention should be paid to the length of the fastening element in question. It can be measured using a stationery ruler. The distance from the bottom of the head to the chamfer is measured.
- To determine the diameter of the bolt, it is recommended to use a micrometer or a template ruler. Experts recommend using a template, since with its help measurements are carried out as accurately and quickly as possible.
- Using a caliper, it is possible to accurately determine the thread pitch; in this case, the distance between individual turns is considered, but this measurement option is suitable for large-sized products. If you need to find out the step parameter of a small part, take 10 turns at once, measure the distance, and divide the result by ten. Note that there are M10 bolts, the dimensions of which are indicated in inches (1 inch = 25.4 mm). But sizes according to GOST are considered traditional in the CIS market.
- The bolt size is indicated in the technical documentation. It can be found in the markings applied to the surface of the product - the first two numbers indicate the diameter, the second - the length of the bolt, the third - the thread pitch. If the marking is not visible, then the size can be determined by measuring the length, thread pitch, and bolt diameter.
Dealing with this issue most often does not arise, but if you have any doubts, then it would be right to seek help from a specialist who will help you deal with the fasteners.
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Wrench sizes
Today, there are universal wrench options that are great for working with different nut diameters. However, cases are different, and the need to select a tool cannot be ruled out. Several options are offered:
- Thread diameter. There is nothing complicated in this case. You can use special devices and tools that allow you to determine the parameters. Or, as an option, look at the information of interest in the technical documentation. Note that if the fastener has a standard thread diameter, then 2 sizes are offered, namely normal and reduced. However, this option is quite rare.
- Head diameter. Depending on the size, the distance of the edges will change: this is what needs to be determined. A ruler is suitable for this. If everything is done correctly, the bolt head will clearly fit into the selected wrench. Of course, it is not always possible to accurately measure a parameter with a ruler, so it would be better to use a caliper.
- Bolt length. The height of the head is not taken into account, only the shaft is considered. If an M16 bolt is required, the thread diameter dimensions should be 16 mm. The marking may also indicate other information: it shows the nominal height of the head, the thread pitch. If you have a car bolt with a pointed tip, then you need to calculate its length taking into account the guide.
Features of marking high-strength hardware
Fasteners belonging to class 8.8 (or higher) represent a group of durable elements for which special requirements are imposed. This also applies to alphanumeric designations - for example, in accordance with GOST of 2006, the marking on the head of carbon steel bolts will look like W11.14 8.8S HL, where:
- W - manufacturer's mark.
- 11.14 - heat batch number.
- 8.8 is a parameter in which the product of the first number and 100 gives the maximum load for the thread, while the second number indicates a tenfold increase in the ratio of yield strength and strength.
- S - Compliance with the category of high-strength fasteners with a large hex head.
- HL - permissibility of operation at low temperatures.
Thus, deciphering the meanings used in labeling is also not particularly difficult - even taking into account the differences between the old and new standards.
Strength classes of threaded fasteners
According to the standard classification, there are seven categories for nuts (4, 5, 6, 8, 9, 10, 12), which, as in the case of hardware, indicate 1/100 of the total limit value determined when calculating the pressure on the structure. However, there are also differences - in particular, these categories apply only to parts with a standard and high profile, while the designations 04 and 05 are applied to the sides of low models, indicating that this option is not suitable for operation under high load conditions.
Types of threaded fastening
The considered principle of connecting elements is based on the use of at least two parts, the first of which has an external thread, and the second - an internal thread. The following types of configurations are distinguished:
- Bolted - the formation of through holes with the subsequent insertion of a rod tightened from the reverse side.
- Screw - in this case, the base itself acts as a retainer, the channels in which are prepared in advance, or - when using self-tapping screws - are formed during the integration process.
- Using studs, one of the ends is screwed into the component part, and the corresponding nut is screwed onto the second in a special way.
Markings
The class indicator - two numbers written through a dot, or sequentially - is one of the most significant characteristics. The first number is used to describe 1/100 of the nominal strength limit of the fastener, measured in MPa, the second shows the ratio of the yield and strength limits, which must be multiplied by 10 to obtain the final value. This, in fact, is the maximum working load of the hardware used - when calculating connections, a coefficient of 0.5-0.6 is used, which excludes exceeding the permissible norm.
What do the numbers on stainless steel bolts mean?
Austenitic products are marked indicating the specific type of alloy (A2, A4), as well as one tenth of the limit value (50, 60, 70) characteristic of carbon compositions.
Ready-made solutions for all areas
Stores
Mobility, accuracy and speed of counting goods on the sales floor and in the warehouse will allow you not to lose days of sales during inventory and when receiving goods.
To learn more
Warehouses
Speed up your warehouse employees' work with mobile automation. Eliminate errors in receiving, shipping, inventory and movement of goods forever.
To learn more
Marking
Mandatory labeling of goods is an opportunity for each organization to 100% exclude the acceptance of counterfeit goods into its warehouse and track the supply chain from the manufacturer.
To learn more
E-commerce
Speed, accuracy of acceptance and shipment of goods in the warehouse is the cornerstone in the E-commerce business. Start using modern, more efficient mobile tools.
To learn more
Institutions
Increase the accuracy of accounting for the organization’s property, the level of control over the safety and movement of each item. Mobile accounting will reduce the likelihood of theft and natural losses.
To learn more
Production
Increase the efficiency of your manufacturing enterprise by introducing mobile automation for inventory accounting.
To learn more
RFID
The first ready-made solution in Russia for tracking goods using RFID tags at each stage of the supply chain.
To learn more
EGAIS
Eliminate errors in comparing and reading excise duty stamps for alcoholic beverages using mobile accounting tools.
To learn more
Certification for partners
Obtaining certified Cleverence partner status will allow your company to reach a new level of problem solving at your clients’ enterprises.
To learn more
Inventory
Use modern mobile tools to carry out product inventory. Increase the speed and accuracy of your business process.
To learn more
Mobile automation
Use modern mobile tools to account for goods and fixed assets in your enterprise. Completely abandon accounting “on paper”.
Learn more Show all automation solutions
The importance of choosing the right fasteners
The products offered by modern manufacturers differ from each other in terms of technical and functional characteristics. Bolts, studs, screws, nuts - to solve each specific problem, the appropriate equipment is required. The main indicators depend on the grade of steel used for manufacturing - when selecting a suitable option, it is worth paying special attention to the parameters that a particular alloy provides, as well as the conditions and the maximum load that can arise during the use of fasteners.
