.250-28 UNF-3B: Understanding the Thread Specification
What is .250-28 UNF-3B?
.250-28 UNF-3B is a thread specification used to describe a type of screw thread. It is commonly used in aerospace and defense industries, as well as in other applications where high-strength, high-temperature resistance, and corrosion resistance are critical.
Breaking Down the Spec
Let's break down the .250-28 UNF-3B specification:
- .250: This is the major diameter of the thread, measured in inches. In this case, the major diameter is 0.250 inches or 6.35 mm.
- 28: This is the threads per inch (TPI) of the thread. The higher the TPI, the finer the thread.
- UNF: This stands for Unified National Fine, which is a type of thread form. UNF threads are similar to UNC (Unified National Coarse) threads, but have a finer pitch.
- 3B: This is the thread class, which refers to the tolerance and fit of the thread. In this case, 3B is a medium-fit thread class.
Key Characteristics
.250-28 UNF-3B threads have several key characteristics that make them suitable for demanding applications:
- High-strength: The thread is designed to withstand high stresses and loads, making it ideal for aerospace and defense applications.
- High-temperature resistance: The thread can operate at high temperatures without compromising its strength or performance.
- Corrosion resistance: The thread is resistant to corrosion, making it suitable for harsh environments.
Applications
.250-28 UNF-3B threads are commonly used in:
- Aerospace and defense industries
- High-performance engines
- Gas turbines
- Compressors
- Pumps
- Valves
Conclusion
.250-28 UNF-3B is a specialized thread specification designed for high-performance applications. Its unique combination of high strength, high-temperature resistance, and corrosion resistance make it an ideal choice for industries where reliability and performance are critical.
