Emma's FAQs
Answer ASTM A325 bolts (now covered under the ASTM International F3125 specification) were originally designed as Heavy Hex Structural Bolts for steel-to-steel structural connections. Because of their strength, clamping force, and intended applications, the Heavy Hex head design remains the standard and most commonly used configuration. However, A325, A490, and Grade 144 bolts can be manufactured in non-standard head styles if they still meet the mechanical... Read more
Short answer: No. Tension Control (TC) bolts are not manufactured in 1-3/8” or 1-1/2” diameters. Under the ASTM F3125 specification, TC bolts are produced up to a maximum diameter of 1-1/4”. What is a Tension Control (TC) Bolt? A Tension Control (TC) bolt, sometimes called a twist-off bolt, is a high-strength structural fastener designed for steel-to-steel connections in construction (e.g., buildings, bridges, and infrastructure projects).... Read more