Threaded Rod & Studs
Simply put, a threaded rod is just a length of metal rod which is threaded from end to end, hence the alternative name of “all thread”. Other names used are threaded bar and threaded stud – they are all the same thing.
Available in a wide variety of types, lengths and materials, threaded rod is one of the most versatile products available for fastening materials together. Typically used to fasten wood and metal objects together, they can also be inserted into wood or concrete, to add stability. They may also be used in plumbing applications.Threaded rods are a popular, versatile product that can be found across a number of industries including electrical, agricultural and construction.
They are ideal for industries where corrosive conditions are an issue; finding a home in plant maintenance and other areas that involve high levels of humidity.
Lengths of all thread can also be found where cleanliness and an aesthetically pleasing appearance are necessary, such as in the plumbing and contractor fields.Other types of threaded rod are located within medical, maintenance and machinery industries due to their anti-corrosive nature.Rods are typically stocked and sold in 3′, 6’, 10’ and 12’ lengths.Threaded bar is most commonly supplied with a right-hand thread (where a clockwise rotation will tighten). Left-hand threaded bar is also available for situations where vibration might cause a right-hand thread to loosen. We can also supply threaded rod with threads at the ends only, or with left/right threads at opposite ends, for specific applications.
Different thread styles are also available, including ACME (or Trapezium) thread, which have a 29° angle and provide a high load bearing capacity,Threaded rods are available in a wide range of materials, including various grades (4.8, 5.8, 8.8, 10.9 and 12.9) of steel, as well as A2 Stainless Steel and A4 Stainless Steel.
Brass, titanium and aluminium threaded rods are also popular, and nylon is increasing in popularity as it is a cost-effective option that is sturdy and lightweight, as well as non-corrosive.
All Thread studs are all threads that are cut to specific lengths as the application demands. There are many grades and materials of all thread studs used across many industries. Cut-to-length all thread rod uses mass-produced rods which are then cut to the finished length with the ends chamfered. Cut thread all thread rod is manufactured for special grades of steel that are not mass produced. These rods are cut slightly longer than the finished length, fully threaded, then cut to the finished length and chamfered on each end. For all manufacturing styles, the all thread rod can then be galvanized or coated per the customer’s requirements.All thread rod or fully threaded studs have two critical dimensions consisting of diameter and length. The length of shorter pieces of all thread rods (studs) can be measured in overall length (OAL) or “first to first”.
First to first measures the stud from its first complete thread on one end to its first complete thread on the other end, eliminating the chamfers on the ends of the studs in the length measurement. Thread pitch can also vary from Unified National Coarse, to 8UN, to Unified National Fine depending on the specification. All thread rod is commonly available in plain steel, hot-dip galvanized and zinc plated. Plain finish all thread rod is often referred to as “black” and it is raw, uncoated steel. All thread rods that will be exposed to the outside elements may need to be hot-dip galvanized to prevent corrosion. Zinc plating can also be used as a corrosion-resistant coating, though a hot-dip galvanized coating will provide greater corrosion-resistance. Zinc plating is commonly used for aesthetic purposes since it can be plated in multiple colors and provides a consistent and shiny coating.Grades and materials include ASTM A193 B7, A193 B7M, A193 B16, A320 L7, A193 B8, A193 B8M, A193 B8 Class 2, A193 B8M Class 2, low carbon and A449 among others. The following is some technical data for several different grades of all thread stud material.
ASTM A307 Grade A
This specification is manufactured from low-carbon mild steel and covers your everyday run of the mill bolts. Stock finishes include plain black, zinc plated, and hot-dip galvanized. One end of each rod requires a permanent grade symbol and manufacturer’s identifier, however this requirement is largely ignored due to their implementation in noncritical applications and the fact that they are often cut to length in the field.
ASTM A307 Grade B
This low-carbon, mild steel bolt specification covers heavy hex bolts and fully threaded studs that are intended for cast iron flanged joints in piping systems with cast iron flanges. A307 Grade B differs from A307 Grade A in that it has a maximum tensile strength requirement. Common finishes include plain black, zinc, and hot-dip galvanized. One end of each rod requires a permanent grade symbol and manufacturer’s identifier.
ASTM F1554 Grades 36, 55, and 105
This specification covers anchor bolts that are designed for anchoring structural supports to concrete foundations. Bolts under this specification can conform to a headed bolt, straight rod or bent anchor bolt configuration. There are three grades within this specification, 36, 55, or 105. These grade numbers represent the minimum yield strength (ksi) requirement of the anchor bolt. The bolts are color coded at the end that will project from the concrete to easily identify the grade used in the field (Grade 36: Blue, Grade 55: Yellow, Grade 105: Red). Permanent stamping with grade symbol and manufacturer’s identifier instead of color coding is a supplementary requirement.
The A449 specification is a high strength grade manufactured from a medium carbon or alloy steel which undergoes a heat-treating process to develop its strength. It is intended for general engineering applications.
Many engineers incorrectly specify A325 all thread rod, which is not a proper specification due to the fact that A325 requires a forged head. ASTM A449 is virtually identical in chemistry and strength to the ASTM A325 specification in diameters 1/2″ – 1″; however, A449 is more flexible considering it is not restricted to a specific configuration. If you have a project with A325 all thread rod specified, have the engineer of record consider moving to an A449 grade instead for diameters 1″ and less. Common finishes are plain black and hot-dip galvanized. One end of each rod requires a permanent grade symbol and manufacturer’s identifier.
ASTM A193 Grade B7
This specification is the other primary grade of all thread rod that is mass produced and readily available off the shelf. It is made from a medium-carbon, alloy steel that has been quenched and tempered to reach its higher strength. This grade of all thread is designed for high temperature or high pressure applications and intended for use in flanges, valves, pressure vessels and fittings.
It is important to note that in this specification, the threading standard for rods above 1” in diameter is 8 threads per inch (tpi). However, B7 threaded rod with Unified National Coarse (UNC) threads is also readily available. Both threading options are stock items so make sure to double check which thread pattern you need for your application. Common finishes are plain black and hot-dip galvanized. One end of each rod requires a permanent grade symbol and manufacturer’s identifier.
ASTM A320 Grade L7
This specification is designed for rods being used in low temperature applications. It is made from medium-carbon, alloy steel which undergoes a heat-treating process to reach the required strength properties and requires a Charpy impact test to ensure its performance at low temperatures. Common finishes are plain black and hot-dip galvanized. One end of each rod requires a permanent grade symbol and manufacturer’s identifier stamp. Please note that rods above 1” in diameter require 8 threads per inch (tpi) unless otherwise specified.
ASTM A354 Grade BC
This specification covers quenched and tempered alloy steel bolts, studs and other fasteners 4” in diameter and under. This is a high-strength specification that does not have configuration limitations and is used for general applications. Common finishes are plain black and hot-dip galvanized. One end of each rod requires a permanent grade symbol and manufacturer’s identifier.
ASTM A354 Grade BD
This grade covers medium carbon, alloy steel that has been quenched and tempered to reach its high strength requirements. It is virtually identical to the A490 specification in chemical and mechanical properties; however, it does not have the configuration limitations that A490 has. If you have a project with A490 all thread rod specified, you should ask the Engineer of Record to consider A354 Grade BD in its place. A354 Grade BD is higher in strength than the other grades listed on this page and is subject to the risk of hydrogen embrittlement when plated or galvanized. One end of each rod requires a permanent grade symbol and manufacturer’s identifier.
SAE J429 Grades 2, 5, and 8
The J429 specification covers requirements for fasteners used for automotive purposes, OEM applications, and other related industries. There are three common grades (2, 5 and 8) that are readily available or can be made as fully threaded rods. There are ASTM specifications that have similar strength properties which may be easier to find in the form of all thread rod than their SAE equivalent. SAE threaded rods do not require permanent grade markings on the ends of the rods like many ASTM specifications do. Common finishes include plain black, zinc plated, and hot-dip galvanized for Grades 2 and 5. Grade 8 is typically provided plain finish only due to the potential risk of hydrogen embrittlement when plated or galvanized.
Stainless steel all thread rod is common in the marketplace and is sold under several different ASTM specifications. The two most common forms of stainless all thread rod are bought and sold simply as AISI Type 304 or Type 316 stainless steel. However, stainless steel all-thread rod is often specified under a variety of ASTM specifications including A193, A320, and F593. The type of stainless steel desired for the project will be specified as a grade within the A193 and A320 specifications or as an alloy group and condition within the F593 specification.