







Internal and external thread bolts, also celebrated as internal and external thread screws or combination screws, epitomize a sophisticated fastening solution that marries the dynamic features of both internal and external threads. These versatile connectors shine in mechanical manufacturing, electronic equipment, furniture assembly, and an array of other industries. Delve into their intricate structural characteristics, innovative working principles, diverse common types, myriad application scenarios, as well as their notable advantages and limitations:
• Structural Features
Ingeniously crafted with a composite thread design, these bolts feature external threads on one end that seamlessly interlock with a nut or a pre-threaded hole. Meanwhile, the opposite end boasts an internal threaded hole, enabling secure multi-layer fastening by connecting additional bolts or screws, thereby catering to complex assembly needs.
Variety in Head Designs: To adeptly cater to a plethora of usage scenarios and operational demands, these bolts flaunt a plethora of head shapes, ranging from cross grooves and straight grooves to inner and outer hexagonal designs, each offering unique functional benefits.
Diverse Material Selections: Typically forged from robust materials such as carbon steel, stainless steel, and copper, these bolts especially favor stainless steel for its exceptional corrosion resistance and unparalleled strength, making it a choice material in demanding environments.
Efficient Working Principle: By engaging the external thread with an internal thread hole on the component, the bolt is anchored securely to one part. The internal thread hole then connects to another screw or bolt, forging a cohesive and stable assembly of multiple components. The ingenious interplay of friction and pre-tightening forces between the threads steadfastly prevents loosening, safeguarding the enduring stability of the connection.
• Common Types
Equal Length Internal and External Thread Bolts: These bolts feature symmetric lengths for their external thread section and internal thread hole section, making them ideal for connecting components of similar thickness with precision.
Unequal Length Internal and External Thread Bolts: With varying lengths between the external thread section and internal thread hole section, these bolts offer flexibility to meet distinct assembly requirements, making them perfect for components with significant thickness variations.
• Application Scenarios
Electronic Devices: In the high-precision realm of electronic device manufacturing, where space is at a premium, internal and external threaded bolts excel in securely connecting multi-layer circuit boards, casings, and other components. They effectively address space constraints and interference issues that arise with conventional, lengthy bolts.
Furniture Manufacturing: Thriving in the assembly of panel furniture, these bolts facilitate swift and secure connection of various panels, ensuring ease of disassembly and transport, while simultaneously providing unwavering structural integrity.
Mechanical Equipment: Essential in mechanical equipment assembly, these bolts proficiently join components like motors, brackets, and transmission devices, ensuring their cohesive operation and maintaining stability amidst the dynamic demands of machinery.
• Advantages and Limitations
Advantages: Streamline the assembly process and minimize parts count; Ideal for constrained spaces or unique structural connections; Ensure hassle-free disassembly and maintenance, significantly boosting production efficiency and maintenance convenience.
Limitations: Though internal and external thread bolts are structurally complex and incur higher manufacturing costs, their connection strength might occasionally fall short of a single high-strength bolt under specific extreme load conditions.