Tension Control Bolts (TC Bolts)
Tension control bolts, also known as TC bolts or Twist Off Bolts, have emerged as a global frontrunner in tensioning high-strength structural bolts. A Twist Off Bolt has a round head bolt with a truncated, flat surface area at the top of the bolt and a 24-sided tip which protrudes from the opposite end. They are available in a wide range of dimensions (5/8” to 1” diameter and 1-1/2” to 7” length) and finishes (including plain and galvanized) to fit your specs.
Frequently Asked Questions on Tension Control Bolts
How do you install a tension control bolt?
1. Place the bolt into the connection with the washer under the nut.
2. Slide the inner socket over the bolt tip and the outer socket over the nut. Press the trigger switch. The outer socket will rotate and tighten the nut until the bolt reaches the required tension.
3. When the proper tension is reached, the tip of the bolt will shear. When the tip of the bolt shears, pull back on the wrench until the outer socket is no longer engaging the nut.
4. Push the ejector lever to discharge the severed bolt.
What are tension control bolts used for?
They are often used for steelwork projects, including bridges, buildings, and other critical structures.
Can tension control bolts be reused?
No, they cannot be reused if there are any signs of wear and tear. The most notable sign would be if the spline has been twisted off, as this denotes the bolt has been permanently elongated and fully tensioned.
Do tension control bolts come with nuts and washers?
Yes, tension bolts come sold in a three-piece fastening system that includes a heavy hex nut and a structural flat washer.
Which grades are tension control bolts available in?
AFT carries TC bolts in ASTN A325 and A490 grades.
