Fasteners

Fasteners, fasteners are used for fastening connections and a wide range of mechanical parts. In a variety of machinery, equipment, vehicles, ships, railroads, bridges, buildings, structures, tools, instruments, meters and supplies can be seen above a variety of fasteners. It is characterized by a wide variety of specifications and performance of different uses and standardization, serialization, generalization of the kind of degree is also very high.Therefore, some people also have national standards of a class of fasteners called standard fasteners or simply standard parts.

Commonly found are the following:

1.bolts: by the head and screw with external threads of the cylinder composed of two parts of a class of fasteners need to be used in conjunction with the nut to fasten the connection of two parts with a through-hole. This form of connection is called bolt connection. Such as the nut from the bolt and can make the two parts separated from the bolt connection belongs to the removable connection.

2.the stud: no head of only two ends with external threads of a class of fasteners. Connection it must be screwed into one end with internally threaded holes in the parts of the other end through the parts with through holes and then screwed on the nut even if the two parts are tightly connected into a whole. This form of connection is called a stud connection is also a removable connection. Mainly used for one of the parts being connected to a greater thickness, requires a compact structure or due to frequent disassembly is not suitable for bolt connection occasions.

3. screws: also by the head and screw two parts of a class of fasteners according to the use of the machine can be divided into three categories of screws, fastening screws and special purpose screws. Machine screws are mainly used for a fastening threaded holes with a through-hole parts of the fastening connection between the parts do not need to nut with this form of connection is called screw connection also belongs to the removable connection can also be used with the nut with two through-hole parts of the fastening connection between. Set screws are mainly used to fix the relative position between two parts. Special-purpose screws such as ring screws for lifting parts.

4. nuts: with internal threaded holes in the shape of the general show for the flat hexagonal cylindrical or flat cylindrical with bolts, studs or machine screws used to fasten the connection between the two parts so that it becomes a whole piece of work.

5. tapping screws: similar to the machine screws, but the threads on the screws for the special self-tapping screw threads. Used to fasten the connection of two thin metal components to become a whole piece of the components need to be made in advance of a small hole due to the high hardness of this screw can be directly screwed into the components of the hole so that the components in the formation of the response of the internal threads. This form of connection also belongs to the removable connection.

6.wood screws: also similar to the machine screws, but the threads on the screw for the special wood screws with threads can be screwed directly into the wooden components or parts used to a metal or non-metallic parts with holes and a wooden component tightly connected together. This connection also belongs to the connection can be disassembled.

7. washers: the shape of a flat ring-shaped class of fasteners. Placed on the bolts, screws or nuts supporting surface and connecting parts between the phase surface plays a role in increasing the contact surface area of the connected parts to reduce the pressure per unit area and protect the surface of the connected parts from being damaged another type of elastic washers can also play a role in preventing the nut back to the role of loose. Common locking mode: mainly for the bolt + lock washer assembly + lock nut + lock bone rubber three forms.

In general: nuts and bolts, studs or screws mechanical properties of the level of matching is as follows:
1. 8 grade nuts can be matched with 8.8 grade bolts, studs or screws
2.10 grade nuts can be matched with 10.9 grade bolts, studs or screws 3, 12 grade nuts can be matched with 12.9 grade bolts, studs or screws In general, the higher performance level of the nut can be used in place of the lower performance level of the nut, such as 10 grade nuts can be used in place of the 8 grade nuts and 8.8 grade bolts, studs or screws.