The abbreviation UNF stands for “Unified National Fine”, this is thread with a fine pitch. The tool for UNF is labeled AF, ANSI/ASME B1.1. UNF threads are most commonly found in the aerospace industry.
NPT stands for National Pipe Tapered threads, also known as ANSI/ASME B1.20.1 pipe threads. It is a U.S. standard for measuring tapered threads on threaded pipes and fittings. Threaded pipes can give an effective seal for pipes using hydraulic fluids. Sometimes referred to as MPT (male pipe threads), NPT threads are not interchangeable with NPS (National Pipe Straight) threads. Unlike straight threads found on a bolt, a taper thread will pull tight, making a closer seal. A sealant compound or PTFE (Polytetrafluoroethylene) tape must be used to ensure a leak-free seal.
What is the difference between unf and npt?
- NPT/NPTF are tapered threads while UN/UNF are parallel.
- Unified threads come in three different classes:
1A(external) & 1B(internal): for applications where a liberal tolerance is required to permit easy assembly even with slightly nicked threads.
2A(external) & 2B(internal): most commonly used class for general applications
3A(external) & 3B(internal): for applications where closeness of fit and/or accuracy of thread elements are important.
QC Hydraulics is supplying all unf and npt thread fittings, please contact our sales team to learn more details.