What Are SAE Thread Sizes | SAE vs NPT Threads & Metric vs SAE

When using fasteners, it’s important to choose the correct thread standard for the specific application. With various systems available, today we are going to go over some key points of SAE thread sizes, what is SAE stand for and what are the common SAE thread sizes? We’ll also talk about SAE vs NPT and SAE vs metric.

What are SAE Thread Sizes?

SAE stands for Society of Automotive Engineers, and SAE thread sizes are a set of standardized thread sizes used in the automotive industry for fastening applications. The SAE thread sizes are based on the inch system of measurement and are used for both internal (female) and external (male) threads. There are two main types of SAE threads: coarse and fine. Coarse threads have fewer threads per inch and are used for applications where strength is the primary concern, such as in engine components. Fine threads have more threads per inch and are used in applications where precision and smooth operation are important, such as in steering and suspension systems.

What does SAE stand for in pipe thread? In pipe threads, SAE stands for Society of Automotive Engineers. However, it’s important to note that the use of SAE threads in pipe applications is not very common. SAE threads are typically used in the automotive industry. In contrast, pipe threads are typically designated by their nominal pipe size and pitch, and are commonly used in plumbing, piping, and other fluid-handling applications. The two most common pipe thread standards are NPT (National Pipe Thread) and BSP (British Standard Pipe). While SAE threads and pipe threads share some similarities in terms of their designation and use in joining applications, they are not interchangeable due to their different thread designs and purposes. When working with pipes and fittings, it’s important to use the correct thread standard for the specific application to ensure a secure and leak-free connection.

What are the most common SAE thread sizes?

1/4″-20 (coarse)

5/16″-18 (coarse)

3/8″-16 (coarse)

1/2″-13 (coarse)

5/8″-11 (coarse)

7/16″-20 (fine)

1/2″-20 (fine)

9/16″-18 (fine)

3/4″-16 (fine)

7/8″-14 (fine)

Are SAE and NPT the Same? - Difference Between SAE and NPT Threads

No, SAE and NPT are different. They are two different types of thread standards used for different types of applications.

SAE threads are used primarily in the automotive industry with an inch system of measurement. SAE threads are typically used for applications where high strength is required, such as in engine components or suspension systems. SAE threads come in both coarse and fine varieties.

NPT threads are used primarily in the plumbing and piping industry and are based on pipe size. NPT threads are tapered and are designed to create a tight seal between pipes and fittings, coming in both male and female varieties.

While both SAE and NPT threads are used for fastening and joining applications, they are not interchangeable.

Metric vs SAE Thread Sizes

Metric and SAE thread sizes are two different standards used for fastening and joining applications, with metric being based on the metric system of measurement and SAE using the inch system.

Metric threads are typically used in applications where high precision is required and are commonly used in Europe and other parts of the world. Metric threads are designated by their diameter and pitch, with the pitch being the distance between threads. For example, an M6x1 thread has a diameter of 6mm and a pitch of 1mm.

SAE threads are commonly used in the United States and are designated by the number of threads per inch, with both coarse and fine threads available. SAE threads are used in applications requiring high strength is required.

What Are SAE Thread Sizes | SAE vs NPT Threads & Metric vs SAE