1. Selection and optimization of thread profile
The thread profile has a key influence on the fastening effect of metal fasteners guide nail. Common thread profiles include triangle, trapezoid, rectangle, etc. Due to the characteristics of its tooth angle, triangular thread has good self-locking properties and is more commonly used in general fastening applications. However, for guide nails that bear large axial forces or need to be frequently disassembled, trapezoidal threads can be considered. Trapezoidal threads have large tooth angles, high root strength, can withstand greater loads, and are not easily damaged during multiple tightening and loosening processes. By accurately calculating and simulating the stress distribution of different tooth profiles under various working conditions, optimizing the parameters such as the angle, height and width of the tooth profile, the thread can evenly transfer stress during tightening, reduce stress concentration points, and thus improve the friction and connection stability between the guide nail and the connected parts.
2. Adjustment of thread pitch and lead
The reasonable setting of pitch and lead is also an important aspect of optimizing thread design. A smaller pitch can increase the number of turns of the thread, provide more contact area within the same axial length, and thus enhance the fastening force. However, too small a pitch may lead to difficulties in thread processing and excessive resistance during tightening. Therefore, it is necessary to determine the appropriate pitch according to the diameter, material and requirements of the connected parts of the guide pin. For example, for guide pins with smaller diameters, if the connection is a softer material, the pitch can be appropriately reduced to avoid damaging the connected material; while for guide pins with larger diameters and high-strength connection requirements, a moderate pitch can be selected and combined with a larger lead to improve the tightening efficiency and tightening effect while ensuring the feasibility of processing, so that the guide pin can be screwed in more smoothly during the tightening process and generate sufficient axial tension to tightly fix the connected parts together.
3. Thread surface roughness and lubrication treatment
The surface roughness of the thread directly affects the friction and wear between the threads. A surface that is too rough will increase the resistance during tightening, and may even cause thread scratches and reduce the tightening effect; while a surface that is too smooth will result in insufficient friction and easy loosening. Through precise processing technology, the surface roughness of the thread can be controlled within an appropriate range, which can not only ensure good friction but also reduce wear. In addition, proper lubrication treatment is also essential. The use of suitable lubricants, such as thread lockers, lubricating oils, etc., can further reduce the friction coefficient between threads, making it easier to tighten the guide nail to the required torque, and in the long-term use process, it can effectively prevent loosening and improve the reliability and durability of fastening.
4. Tolerance design of threads
Accurate thread tolerance is crucial to improving the fastening effect of metal fasteners guide nail. The tolerance between the external thread of the guide nail and the internal thread of the connecting part should be designed according to the specific application scenario. Too loose fit will cause the guide nail to shake in the hole and fail to provide sufficient fastening force; too tight fit will make the guide nail difficult to install and may even damage the thread. By adopting a reasonable tolerance grade, such as the base hole system or the base shaft system, combined with appropriate clearance fit, transition fit or interference fit, ensure that the guide nail can fit tightly with the connecting part after installation, evenly transfer the load, and maintain good fastening performance under complex working conditions such as temperature changes and vibrations, effectively preventing the connection from loosening or failure.
