Threaded rod is a fastening bar or a rod threaded along its length. Thread direction is an important specification to consider. Choices include right hand, left hand, or both right hand and left hand. Right hand threads are configured so that clockwise rotation tightens the threaded rod to a fastener. Left hand threads are less common, but well-suited for applications in which motor vibration would cause right handed threads to loosen. When thread direction is not specified, the default direction is usually to the right. Left handed threads are usually listed explicitly. Threaded rod with both right hand threads and left hand threads have right threads at one end of the rod, and left threads at the opposite end. This dual thread style is used for specialty assemblies such as turnbuckles.
Threaded rod can be made of aluminum, brass, bronze, silicon bronze, copper, and proprietary alloys such as Inconel® and Incoloy® (Special Metals Corp.) Aluminum is a bluish, silver-white, malleable, ductile, light, trivalent, metallic element with good electrical and thermal conductivity, high reflectivity, and resistance to oxidation. Brass has good strength, excellent high-temperature ductility, reasonable cold ductility, good conductivity, excellent corrosion resistance, good bearing properties and low magnetic permeability. Copper is a reddish metallic element that is ductile and malleable and is one of the best conductors of heat and electricity. Bronze contains copper as its main alloying metal. Silicon bronze is another common material for threaded rod.
Steel, stainless steel, and titanium threaded rod is commonly available. Steel is iron that contains carbon in any amount up to about 1.7 percent as an essential alloying constituent. Stainless steel is chemical and corrosion resistant and can have relatively high stress ratings. Other types of steel include carbon steel, alloy steel, and hardened steel. Titanium is strong, lightweight, and suitable for a variety of aerospace and medical applications. When alloyed with steel, titanium adds strength and oxidation resistance to threaded rods.
Metallic threaded rod can be anodized, treated with black oxide, chrome galvanized, phosphate coated, or plated with silver, gold, tin, zinc, or zinc chromate. Non-metallic threaded rod can be made of plastic, fiber-reinforced plastic, nylon, polyvinyl chloride (PVC), polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), or synthetic rubber.