Expansion screws are a necessary tool when we decorate our houses. They can fix items and be beautiful. However, due to differences in specifications and models, you need to pay attention to some issues when purchasing. The following is the expansion screw specifications and models introduced by the editor and how to find the appropriate expansion bolt specifications.
1. Expansion screw specifications and models
Expansion screws on the market are mainly used on walls, fixtures and columns, with specifications generally ranging from 3.6, 4.8, 6.8, 8.8, 9.8 and 12.9. The decimal points after these numbers represent the nominal tensile strength and yield ratio of the bolt material respectively. For example, a bolt of grade 8.8 means that the tensile strength of its raw material can reach 800MPa, and the yield-to-strength ratio can reach 0.8.
2. How to look at the specifications of expansion bolts
When purchasing expansion bolts, we need to pay attention to its thread mark and size number. The thread mark generally uses the letter M, and the size number indicates the diameter of the thread. For example, M14 indicates that the diameter of the metric bolt is 14 mm. The complete thread marking includes thread feature number, dimension number, tolerance zone number and other combinations, ultimately forming a standard number.
The bolt size number is generally composed of the nominal diameter and the pitch. For coarse threads, the marking can be omitted, while the size number of the multi-thread thread is the nominal diameter multiplied by the Ph lead and the pitch. Tolerance zone numbers generally include numbers and uppercase letters or lowercase letters. Internal threads generally use uppercase letters, and external threads generally use lowercase letters, such as 7H, 8g, etc.
The thread engagement length is also an important mark, generally represented by S, N or L, where S stands for shorter, L stands for longer, and N stands for medium. If the thread engagement length is not indicated, the tolerance zone is generally determined based on the medium engagement length (N). If necessary, you can also indicate the screwing length in the remarks.
Through the above introduction, I believe everyone has understood how to choose suitable expansion screws and bolts. When decorating, be sure to choose the correct specifications and models to ensure the safety and beauty of fixed items.
