Although A307 grade C and F1554 grade 36 are virtually identical, there are some subtle yet very important differences. The ASTM F1554 specification was introduced in 1994 and covers anchor bolts designed to anchor structural supports to concrete foundations. F1554 grade 36 is manufactured from low carbon steel just like ASTM A307 grade C was but in addition to being a bent or straight anchor bolt, can also be a headed bolt that is embedded in concrete and used for anchoring purposes. Most commercially available all thread rod that meets ASTM A307 and is used for anchor bolts will not meet ASTM F1554 grade 36. Additionally, imported A307 hex bolts that are commonly embedded in concrete and used as anchor bolts will not meet F1554 grade 36. However, many fastener distributors and even some manufacturers who do not have a thorough understanding of the differences between ASTM A307 grade C and F1554 grade 36 continue to provide A307 bolts believing they will cross-certify to ASTM F1554 grade 36 which is simply not the case in most instances. It is important to be aware of the differences between these two specifications to limit exposure to unnecessary liability.

Answer: In some respects SAE J429 grade 8 bolts and ASTM A490 bolts are similar, and in other respects they are different. The first thing to address is the fact that these specifications are covered by different organizations. SAE (Society of Automotive Engineers) covers bolts for automotive, equipment, and OEM applications, whereas ASTM (American Society for Testing and Materials) covers fasteners for construction applications. By nature, SAE bolts are finished cap screws and are more precision fasteners than ASTM bolts.

Now let’s address the similarities… Both bolts have very similar chemical requirements (medium carbon alloy steel), strength properties (150ksi minimum tensile strength), and size range (maximum 1-1/2” diameter). The difference lies in the application and configuration of the fasteners. ASTM A490 bolts are a heavy hex head structural bolts designed for structural steel connections, while SAE J429 grade 8 bolts are finished cap screws with a standard size hex head and used in many equipment and automotive applications. Because A490 bolts are designed for structural connections, they will have a shorter thread length than grade 8 bolts.

Answer: Every ASTM standard is identified by a unique designation. It includes a capital letter (A - H), followed by a serial number ranging from one to four digits, a dash, and finally the year of issue. For example, a common bolt specification is A449 - 07a, although when specified the standard’s year designation is usually not included.

The alphabetical letters represent general classifications. Outlined under each classification are a number of standards for a variety of products, materials, testing processes, and many other topics.

General ASTM Classifications

1. Ferrous Metals
2. Nonferrous Metals
3. Cementitious, Ceramic, Concrete, and Masonry Materials
4. Miscellaneous Materials
5. Miscellaneous Subjects
6. Materials for Specific Applications
7. Corrosion, Deterioration, and Degradation of Materials
8. Joint Committee and District Recipients

ASTM Letter Designations

Thanks to Leslie who posted a comment to our “Ask a Question” and actually answered this question.

Answers: All bolts we manufacture are made to imperial measurements. The primary reason for this is because the steel used to make bolts is milled to imperial sizes. Even though metric measurements are almost exclusively used internationally, most raw materials are only available domestically in inches.

Often projects, such as highways, bridges, and power plants specify fasteners to metric sizes. In these cases engineers will typically approve “soft conversions” from metric drawings to the nearest imperial measure. For example, a request for 22mm bolts would be converted 7/8 of an inch. In the case where a soft conversion is not an option, we can offer custom fasteners machined to metric dimensions or discuss other possible solutions.

It seems like this question is directed toward clevis pins that are used to connect control assemblies, linkages and perhaps hinges. In these applications where rotation of the clevis pin is anticipated, I agree that a washer would protect the retaining device from possible ’side effects’ of the rotation.

In the case of pins that are used in structural support and bracing applications, I think that it is safe to assume that pin rotation does not occur because the loading is largely static, or at least non-reversing (there is no push-pull going on). I think that it is also safe to assume that there is no load at all on the retaining device (cotter pin) if the pin is installed correctly, and that a washer would provide no added value.

As a side note, it is my belief that what we call headed pins (and the rest of the world calls clevis pins) are described in the AISC Steel Construction Manual as “horizontal or vertical pins” because they can be used in applications where the pin is oriented vertically, with the head bearing on the top surface of the connected member, without concern that the cotter pin could be damaged from physical abuse or corrosion and allow the pin to fall through.

It’d be great to hear your thoughts on this topic in the comments.

Answer submitted by Paul Doherty

Answer: ASTM A325 and SAE J429 grade 8 are not the same fastener. As a matter of fact, they couldn’t be more different. SAE (Society of Automotive Engineers) establishes specifications covering fasteners intended for use in automotive, OEM, and equipment applications, while ASTM (American Society for Testing and Materials) provides specifications for construction fasteners. There are several differences between these two bolts, including chemistry, strength, application, and dimensional tolerances. A325 bolts are typically manufactured from a medium carbon steel (although they can be made from an alloy) while SAE grade 8 bolts are made from a medium carbon alloy steel. Grade 8 bolts are significantly stronger than an A325. An ASTM specification with similar strength properties to grade 8 is ASTM A490. Compare strengths with our strength by grade chart.

ASTM A325 bolts are heavy hex structural bolts and used in structural steel connections, while SAE grade 8 bolts are finished hex bolts and typically used in automotive and equipment applications. By nature, an SAE bolt is also a more precision fastener with tighter tolerances than an ASTM bolt.

Answer: Most ASTM standards address the recommended application of the fastener. There are often two or three different ASTM specifications with similar chemical and mechanical properties, but with differing applications. ASTM F1554 is a specification that is designed for anchor bolts embedded in concrete. Since your application is for tie rod assemblies, it would appear that technically, you should select a different specification with similar properties to the F1554 grade 105 specification. In this case, you should consider using ASTM A354 grade BC which is virtually identical to F1554 grade 105 both chemically and mechanically, but is not limited by its application. For a strength comparison of these two grades refer to our strength by grade chart.

Chemically, we manufacture both grades of fastener using the same medium carbon alloy steel (4140). The strengths of these two grades are virtually identical with only subtle differences. F1554 grade 105 has a 105,000 pounds per square inch (psi) minimum yield strength while A354 grade BC has a minimum yield requirement of 109 ksi. The minimum tensile strength requirement of both grades is identical at 125 ksi with F1554 grade 105 also possessing a maximum requirement of 150 ksi. From a manufacturing perspective, we make these bolts in the same way using identical raw material. We certify the finished product based on the end use application of the bolt and based on the requirements of the customer.

If you are considering a larger diameter F1554 grade 55 for this application, there is not a straightforward substitution. Many engineers specify A572 grade 50 (50 ksi minimum yield instead of 55 ksi). We often manufacture rods to this grade, although A572 is really a steel specification and not a bolt specification. There are no other ASTM grades that are similar. Therefore, if you want the chemical and mechanical properties of the F1554 grade 55 specification for a tie rod application, there is no reason you still can’t specify this grade of fastener even though technically it should only be used for an anchor bolt.

Portland Bolt’s view of ASTM specifications is that they are simply guidelines. They are used to order product so that a purchaser has a reasonable expectation as to what they will be receiving when they order based on the requirements of a given specification. However, any aspect of a given specification can be altered provided there is complete understanding and agreement on what changes are being made to a given specification. For example, let’s say in this application that you wanted to use the A354 grade BC specification due to the application instead of F1554 grade 105, but it was critical that the tensile strength not exceed 150 ksi as is the case with the F1554 grade 105 specification. You could certainly stipulate that the bolts be ordered and manufactured to the A354 grade BC specification with the tensile strength NOT to exceed 150 ksi. Likewise, there is no reason you can’t specify the use of F1554 grade 55 rods for a tie rod application if that specification of rod gives you the mechanical values that you are looking for as long as you, the buyer, and the manufacturer all understand that the end use application is different than the intended application of the F1554 specification.

The raw material cost for F1554 grade 105 or A354 grade BC is approximately 50% more expensive than F1554 grade 55 raw material. All of these grades of steel are currently available in our inventory. The raw material for both F1554 grade 105 and A354 grade BC is commonly available in 24 foot lengths while F1554 grade 55 raw material is available in 20 foot lengths. If you would like us to put together budgetary pricing or comparison pricing for you please provide us with a specific list of quantities, grades, and sizes and we will be happy to provide you with a cost estimate.

As always, feel free to submit your questions.

According to section 9 of the ANSI B18.2.1 specification, which covers dimensional tolerances for hex bolts, A325 and A490 structural bolt 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 money in the long run by producing all of their sizes slightly shorter than the advertised length. It doesn’t make sense but that’s the way it is. The chart below outlines the allowable tolerances under ANSI B18.2.1.

Bolt Length Tolerances

When considering bolt lengths for specific applications keep these length tolerances in mind. Also, remember RCSC Specification Section 2.3.2 recommends to ensure proper thread engagement the end of the bolt should be at least flush with the nut. These bolt tolerances are especially important when working with short bolt lengths. AISC offers a formula for calculating correct lengths to order bolts under Table 7-15 (7-80).

For example, the production of a 1” diameter X 12” long A325 bolt begins by cutting a 20’ length of 1045 steel round bar into 13-11/16” pieces. Since the finished bolt length of 12” is measured from the end of the bolt to the underside of the head, we must add 1-11/16” to the cut length of the bolt. After cutting the bolt to length, this added material (1-11/16”) is heated to approximately 2000 degrees Fahrenheit and forged into whatever head style the specific bolt requires. In the case of an A325 bolt, the head style is a heavy hex structural bolt. After the head is forged, an A325 bolt undergoes a heat treating process in which the bolts are quenched and tempered to develop the high strength mechanical properties required by the specification. The next step in the process is to test the bolts to ensure that they meet the strength requirements of the A325 specification. Portland Bolt performs this mechanical testing in-house. After verification that the A325 bolts comply with the strength requirements of the specification, they are threaded with 1-3/4” of 8 pitch Unified National Coarse thread. If the final product is to be hot-dip galvanized, Portland Bolt also performs this process in-house. By viewing the virtual tour of the Portland Bolt manufacturing facility on our home page, you can see the forging operation being performed.