Threaded Rod vs Bolt: What’s the Difference?

In the world of fasteners, the level of choice can be bewildering, with hundreds of different types, finishes and sizes. In some cases, products will have a different name but do the same job.

One of the common mix-ups is the difference between a threaded rod, and a bolt, and where they are best suited. In this blog we’ll take a look into bolts and threaded rods, and what the difference is.

What is a Bolt?

As the most commonly used item of mechanical fastening, the humble bolt is everywhere in the industry. By definition a bolt is a helically threaded fastener that is used to attach two or more parts, usually using a corresponding nut and in many cases a washer.

One distinction, not everyone knows or uses is that a bolt is typically not fully threaded but has a plain shank under the head. A bolt differs from a screw in that a screw is not used with a nut, but is inserted into a pre-threaded hole in another part, or makes its own thread.

Bolts are available in a wide array of finishes and materials, from zinc-plated steel to high-strength stainless steel or even titanium. The head type can also be specified, hex heads are the most common, which are tightened with a wrench or socket, but Allen hex heads, Torx, Robertson and Phillips head bolts are also widely used.

Benefits of Using Bolts

• Lots of head choices available
• Faster to install – when a known length is required
• Stronger grades available
• They look more professional

What is Threaded Rod?

Threaded rod, also known as ‘threaded stud’, or ‘studding’ is a helically threaded fastener, without a head or plain shank. It is available in sizes much longer than bolts, often being sold in 3ft or 9ft lengths.

Threaded rod is available in a range of diameters and multiple grades, finishes and materials including zinc-plated or stainless steel.

Benefits of Using Threaded Rod:

• Versatile to use in the field
• Can be used as a bolt if needed
• Easier to source from suppliers as an exact length not needed

What Is The Difference Between A Bolt And Threaded Rod?

Threaded rod is used where a conventional bolt is too short, or a more versatile approach is needed. A threaded rod can act as a makeshift bolt using a nut or two but can be carried in long lengths and be cut when needed.

As it has no head, unlike a bolt. threaded rod also allows nuts or washers to be added from either end, meaning it’s great for tensioning systems, or support elements in industries such as electrical and HVAC, where versatile installation methods are needed.

When Should You Use Bolts or Threaded Rods for a Project?

Picking between threaded rods and bolts for your project can depend on a few factors, including the complexity of the design, time constraints and more:

Does the Design Allow Bolt Lengths to be Exact?

If your project is made from clearly defined components, with known thicknesses, lengths and dimensions, then specifying the right length and grade of bolt should be easy and will provide a better solution.

Does the Joint Need To Withstand High Loads?

Whilst high-strength threaded rod is available, it is most commonly found in grade 4.6 or 8.8, Bolts, however, can be easily found in grade 9.8 up to 12.8, making for a much stronger fastening.

Does the Project Need Adjustability?

If you’re using the fasteners in a new environment, such as installing components on-site, with varying layouts, then the threaded rod is ideal, it can be carried in 9ft lengths and cut to suit any application.