The Eurolink Blog

Metric Fastener Thread Types

Written by Team Eurolink | Apr 7, 2020 3:00:00 PM

There are several metric fastener thread types that Eurolink Fastener Supply Service sources. These are some of the most common types.

  • UNF
  • UNC
  • BA
  • BSF

We'll explain each one and the common uses for that thread type. Thread types can be more prominent in some regions of the world compared with others.

Metric Fastener Thread Types Explained

Metric threads are available in fine and coarse threads. In addition to the thread’s coarseness, you can select from a variety of materials for the fastener to be made of.

The various coarseness and materials each serve their own purpose. While you might use a very coarse thread for one industry, another industry might favor a finer thread for its purposes. Coarser fasteners are easier to find and more commonly used.

Fine threads are not well suited for high-speed assembly. However, they are often better for fastening hard material using less torque. The finer the thread, the less tendency the fastener has to loosen.

Here’s a definition of each of the most common thread types.

UNC

Unified Coarse (UNC) is the most common metric fastener thread type for the U.S. Agriculture is an industry that uses UNC frequently. That’s because these are strong, coarse threads.

The deeper, more generic threads make these fasteners easier to remove. However, they also have a high tolerance for the manufacturing industry.

UNF

Unified Fine (UNF) is another popular thread in the U.S. These tight, fine threads are common in the automotive and aerospace industries. You’ll see these threads most commonly used in steel and stainless steel.

They are heavy load bearing and better torque locking than UNC.

BA

British Association (BA) are old-style British thread fasteners dating back to 1884. They have numbered diameters and were standardized in 1903. Most commonly, these thread types are used in electrical fittings.

However, because this is a British-style fastener, it’s slowly phasing out in favor of UNF and UNC since these are more universal metric styles. Additionally, you’ll struggle to find BA style fasteners in small screws.

BSF

British Standard Fine (BSF) is another type of British thread. You’ll find these threads in both steel and stainless steel. It’s most commonly used on vintage cars and machinery. Just like BA, it’s harder to find due to a heavy favor for metric threads.

As the name implies, these are finer thread bolts, screws, and nuts compared to BA fasteners.

Finding the Right Fastener for the Job

With so many metric fastener thread types, you need a supplier that offers a wide variety. Eurolink Fastener Supply Service is your trusted partner for even the hardest-to-find metric fasteners.

Contact us for information and pricing on a wide selection of fastener types, sizes, and materials.