Portland's FAQs

A320 Grade L7 vs. A320 Grade L7M

What is the difference between ASTM A320 Grade L7 and A320 Grade L7M?

ASTM A320 possesses several fastener grades manufactured from either alloy or stainless steel and are intended for cold temperature applications. Both Grade L7 and L7M are manufactured from a quenched and tempered alloy steel. While the chemical requirements for both Grades L7 and L7M are identical, there are several differences that separate the two grades.... Read more

Dimensional Standards

Which standard defines dimensions for bolts, nuts, and washers?

The organization that is responsible for addressing dimensional guidelines and tolerances for fasteners is the American Society of Mechanical Engineers (ASME). This organization was founded in 1880 and now has over 130,000 members in 151 countries. In addition to being a standards organization, ASME is also involved in research and development, training and professional development,... Read more

High Strength Square Nuts

Are high strength square nuts readily available?

Most square nuts in the marketplace are made from low or medium carbon steel and are typically used with square head bolts. Their strength is not compatible with high strength bolts.  These nuts are readily available in plain finish and hot-dip galvanized and are typically mass produced overseas. If you are looking for high strength... Read more

Engineers on Staff

Does Portland Bolt have any engineers on staff to help design my project?

Unfortunately, Portland Bolt does not have any engineers on staff. For this reason and due to liability issues, we are unable to make recommendations with regard to quantity, size, configuration, or grades of fasteners for specific applications. By the time we get involved in manufacturing bolts for a construction project, an architect and engineer have... Read more

Bridge Washers

What is a bridge washer?

This is a term that is frequently used across the industry. More often than not, “bridge washers” will refer to cast iron malleable iron washers. These washers are typically used in dock and wood construction. Malleable iron washers are specifically designed to prevent bolt heads and nuts from pulling into the wood. Detailers will also... Read more

A325 Lag Screws

Can Portland Bolt manufacture A325 lag screws?

Even with the new F3125 specification that covers A325, Portland Bolt would not manufacture lag screws to F3125 Grade A325. According to section 1.2.1 under Intended Use in ASTM F3125, “Bolts manufactured under this specification are intended for use in structural connections covered in the Specification Joints Using High-Strength Bolts, as approved by the Research... Read more

Unified National Fine Thread Series (UNF)

Can Portland Bolt manufacture fasteners to Unified National Fine Thread Series (UNF)?

Unfortunately, Portland Bolt cannot manufacture fasteners with Unified National Fine threads. UNF thread series bolts are typically used in precision applications, such as automotive or machinery. Our threading equipment is unable to hold the required thread tolerance for UNF. Also, unlike cold-drawn steel, the hot rolled round bar we use to manufacture construction fasteners does not lend itself... Read more

A193 Grade B7 vs. SA193 Grade B7

What is the difference between A193 Grade B7 and SA193 Grade B7?

A193 is an ASTM (American Society for Testing and Materials) specification, whereas SA193 is from ASME (American Society of Mechanical Engineers). ASME repurposed the ASTM specification and added an “S”. The primary difference is the application.  While both specifications are designed for high temperature / high pressure service, SA193 may also be used in nuclear... Read more

A687 Fasteners

Can I order bolts to the ASTM A687 specification?

ASTM A687 was withdrawn in 1999. The specification covered high-strength non-headed steel bolts and studs.  Below are the mechanical properties as well as Charpy Testing requirements: Yield Strength (KSI) Tensile Strength (KSI) Elongation % Reduction of Area % Foot-Lbs (Ave-min) Temperature 105 Min. 150 Max. 15 Min. 45 Min. 15 -20F While it is possible... Read more

1/2″ A490 Bolts

Why can’t I find 1/2” diameter A490 bolts?

ASTM F3125 Grades A490 and A325 structural bolts are mass-produced through 1-1/4” diameter. However, there is an exception for 1/2” A490 bolts. Compared to other diameters, these are not commonly used. Therefore, 1/2” diameter A490 bolts are not mass-produced and are not readily available in the marketplace. There are a couple of ways to work around this. First,... Read more