Greg's FAQs

I have a client out of Israel and they manufacture equipment for use in power plants. They have a question about anchor bolts in seismic zones. They want to use anchor bolts made from SAE 4340 material and they would like to know if that is equivalent to ASTM F1554 material. Will this material be... Read more

A tap bolt is (typically) a fully threaded hex bolt, while a cap screw is (typically) a hex head bolt that will be installed by turning the head of the bolt (screw) instead of tightening it with a nut. Usually cap screws are being threaded into something (a piece of machinery for example), rather than... Read more

Your page says A320 requires bolts or cap screws to have heavy hex heads. I have the 2003 edition of A320 and can’t find that requirement. Where is that requirement stated? The ASTM A320 specification does not specifically address the physical dimensions of headed bolts. However, it does refer you to ASTM A962 for some... Read more

It not uncommon for us to get requests or for bolt configurations that don’t match the specifications. Anchor bolts called out as headed Grade 8 bolts are only available with a hex head. From your description ASTM A354 BD would be the correct fastener. This specification has mechanical properties that are very similar to SAE... Read more

We do not recommend allowing this type of substitution without approval from the Engineer of Record. Based on performing mechanical tests to the ASTM specification F606 which covers the testing of construction fasteners, a rod with a nut would typically not produce the same strength characteristics as a bolt with a forged head. Under F606,... Read more

Engineers often design anchor bolts in one of four common configurations. We see anchor bolts with forged heads, 90 degree bends, straight rods often with anchor plates on the bottom, and swedged rods. Engineers will design a structure using different grades and configurations based on the size, weight and design of a structure, wind forces,... Read more

Portland Bolt forms threads using two methods: cut threading and roll threading. Cut threading is a process that removes steel to form the threads. The roll threading method we utilize starts with reduced body pitch diameter steel. To make a one inch bolt we would use .912 inch round bar. This steel is forced between... Read more

Generally speaking, bolts over 1-1/2″ in diameter should be designed in 1/4″ increments, regardless of grade. While it is possible to manufacture bolts in 1/8″ increments (i.e. 2-3/8″), there are several reasons why you would want to avoid it. Steel Availability Steel round bar used to manufacture bolts is not readily available in 1/8″ increments over... Read more

The “X” designates the connection type (bearing-type connection with threads excluded from the shear plane) and has nothing to do with the bolt itself. Therefore, an A325 structural bolt used in this type of connection will have no different markings than an A325 bolt used in a different type of connection (N or SC). All A325... Read more

The term “high strength” is a somewhat ambiguous fastener term. Most people in the industry would interpret the phrase “high strength” to refer to any bolt that has been quenched and tempered (heat treated) to develop its strength. Additionally, the ASTM specification F1554 Grade 55 is commonly referred to as being manufactured from a “high... Read more