Introduction to Threaded Rod
Welcome to Threaded 101, the place to get your basic threaded product questions answered. In this blog series, we will cover four common topics to help build the foundation you need to better understand the threaded fastener industry. We will cover materials used to manufacture threaded products, the importance of tensile strength, finishes that will work best for your application, and the basic dimension information for threaded products.
What is Threaded Rod?
Let’s start by defining what threaded rod is – it is simply a piece of steel rod that has been threaded along its length. Threaded rods are used in general purpose applications in multiple industries including, but not limited to, electrical, general construction, OEM, and the pipe valve and fitting industries. The thread direction is a critical component to consider with threaded products. There are three main types of threading:
Threads are configured so a clockwise rotation will tighten the threaded rod to the fastener.
Threads are configured so a counter-clockwise rotation will tighten the threaded rod to the fastener.
Both Right and Left Hand
Threads are configured so each end of the rod will have different thread directions (right on one side and left on the other).
In addition to thread direction, the length of the threaded product is important to clarify, as different lengths and thread types are referred to by different names. Generally speaking, if the product is less than 12 inches long, it is called a stud. If the product is 12 inches or longer, it is called a threaded rod. For stud thread types, there are three main options on the market: fully threaded, which is threaded from end-to-end, or single-end and double-end. A single-end stud only has threads on one end of the stud. A double-end stud has threads at both ends and an unthreaded center section, which is typically called the blank. The length of threads on a double-end stud can either be equal or unequal, which means there could be more threads on one side than the other.
Threaded products come in a variety of finishes and materials. The product application will help you determine which product and material you need. No matter what the size, shape, color or material used, these products are all designed to be used under a specific amount of tension, which is the breaking point of the material.
As for types of metal used in the manufacturing of threaded rod, the most common include low carbon steel, B7 and stainless steel. However, other metals used include: Grade 5 and Grade 8, stainless steel 303, 304 and 316, A449, Brass, aluminum, copper and silicon bronze. In the next Threaded 101 blog post, we will provide more in-depth information on threaded rod materials. For now, head to the cababilities section of our website to learn more about the materials used in the threaded rod industry.
When choosing the material for your threaded product needs, it is important to know what tensile strength is required for the application, so the right material is purchased to withstand the pressures of the application. Tensile strength is the maximum tension which can be applied prior to fastener fracture and failure. This will be designated by an engineer and listed on the spec of the project. In the coming weeks, we will provide more in-depth information regarding yield strength, ultimate strength and breaking strength in the tensile strength post of our Threaded 101 series. Learn more about yield strength, ultimate strength and breaking strength in the tensile strength section.
Threaded product finishes depend on the use or application for the product. The most common finishes are zinc chromate (clear zinc), zinc dichromate (yellow zinc), black oxide, and hot-dip galvanized.
Size and Dimensions
With so many different shapes and sizes, dimensions can be complicated. The important dimensions to know and measure with threaded products are the diameter, the thread pitch, and the length. Thread pitch measures the amount of threads per inch. There are four main thread pitch measurement types: course threaded UNC (the most common), fine thread UNF, 8 pitch 8UN and Acme Thread. For the length, identify if the overall length of the product is being measured, or from first thread to first thread (see Figure 1 below). Another area of measurement for double-ended studs is the “toe”, which refers to the threading on the end of the product. Toe lengths can be equal or unequal on the threaded product. For example, the product can be a 20” overall length double-ended stud, with a 2-inch toe on one end, and a 6-inch toe on the other end. This is just the beginning of identifying the correct dimensions of threaded products. Once you have these dimensions, you can be confident that your ordered all thread will fit and take the nut provided.
As you can see, the threaded rod industry is complex, with thousands of products covering several industries. To help you learn more about these products and determine what will work best in your application, keep an eye out for the upcoming blog posts in our Threaded 101 series!
Let us know if you have any questions in the comment section!