Expansion screws are a necessary tool when we decorate the house, which can fix items and be beautiful. However, due to the differences in specifications and models, some problems need to be paid attention to when purchasing. The following is a small series of expansion screw specifications for you to introduce the model and how to find the appropriate expansion bolt specifications.
The expansion screws on the market are mainly used for walls, fixed equipment and columns, and the specifications are generally 3.6, 4.8, 6.8, 8.8, 9.8 and 12.9. The decimal points after these numbers respectively indicate the nominal tensile strength and flexion ratio of the bolt raw material. For example, a bolt of class 8.8 indicates that the tensile strength of its raw material can reach 800MPa and the flexor ratio can reach 0.8.
When purchasing an expansion bolt, we need to pay attention to its thread mark and dimension number. Thread marking generally uses the letter M, and the size number indicates the large warp of the thread, such as M14 indicating that the large warp of the metric bolt is 14 mm. The complete thread marking includes the thread feature number, dimension number, tolerance zone number, and other combinations to form the standard number. The bolt size number is generally composed of the nominal diameter and screw moment, and the mark can be omitted for coarse thread, while the size number of multi-thread is the nominal diameter multiplied by the Ph lead P screw moment. The tolerance band number generally has numbers and uppercase letters or lowercase letters, the internal thread generally uses uppercase letters, and the external thread generally uses lowercase letters, such as 7H, 8g, etc. The length of the thread is also an important marker, which is generally expressed by S,N or L, where S represents short,L represents long, and N represents medium. If the screw length is not indicated, the tolerance zone is generally determined by the medium screw length (N). If necessary, the length of the spin can also be indicated in the remarks. Through the above introduction, I believe you have understood how to buy the right expansion screws and bolts. When decorating, we must pay attention to the correct specifications and models to ensure the safety and beauty of fixed items.
