Greg's FAQs

Structural Bolt Length Tolerance

According to section 9 of the ASME B18.2.6 specification that covers fasteners for use in structural applications, an A325 structural bolt can actually be produced .12” to .25” less than the published length and still meet the specification.

According to section 9 of the ASME B18.2.6 specification, which covers dimensional tolerances for hex bolts, A325 and A490 structural bolts can actually be produced between .12 to .25 of inch less than the published length and still meet the specification. This small difference isn’t much, but mass bolt producers save a significant amount of... Read more

How a Bolt Head is Formed

How is a bolt head formed?

What many people do not realize is that the head of a bolt is formed by heating the end of a piece of steel round bar and then forging (reshaping) the heated end into a head. The head is not welded on or otherwise “attached” to the end of the round bar. For example, the... Read more

ASTM A193-B7 Thread Pitch

What bolts are available in ASTM A193-B7 and what is the appropriate thread pitch to specify?

“My plant uses hex head cap screws, ASTM A193-B7 as standard. We typically stock the constant thread series 8 TPI fasteners above 1 inch diameter. However, many tapped items like expansion joints come with UNC thread counts, like 7 threads per inch (TPI) for 1-1/4″ diameter bolts. This causes a problem sometimes when fasteners don’t... Read more

ASTM A325 Anchor Bolts

Can ASTM A325 grade be used as anchor bolts?

We often sell A325 heavy hex bolts as anchor bolts, but technically they are supposed to be used for structural steel connections only. Part of the problem is that the A325 specification is very specific as to the application and thread length. Because A325 bolts are typically used in structural steel connections, they have very... Read more

Imported ASTM A307 All Thread Rod

Does imported stock all thread rod meet ASTM A307 grade C?

Frequently, imported mild steel all thread rod will not meet ASTM A307 grade C. The three different grades of the A307 specification identify their intended application where grade C is embedded in concrete and used for anchoring purposes, grade B is used in cast iron flange connections, and grade A covers general applications. Normally, imported... Read more

Bolt Shear Strength Considerations

What is the shear strength of carbon steel bolts?

First, unlike tensile and yield strengths, there are no published shear strength values or requirements for ASTM specifications. The Industrial Fastener Institute (Inch Fastener Standards, 7th ed. 2003. B-8) states that shear strength is approximately 60% of the minimum tensile strength. “As an empirical guide, shear strengths of carbon steel fasteners may be assumed to... Read more

California School Projects

Are roll threaded anchor bolts with a reduced body allowed on school projects in California?

Contrary to popular belief, roll threaded anchor bolts are acceptable for schools in California. Portland bolt has spent the last three years working with the California Department of General Services Division of the State Architect to dispel the rumor that only full body cut threaded bolts could be used. The link at the bottom of... Read more