Newest FAQs

Stainless Steel Bolt Differences

What are the differences between hex bolts ordered as type 304 stainless steel, A193 Grade B8, and F593 Group 1 (type 304 stainless)?

Hex bolts are often ordered as a type 304 stainless and not to a specific ASTM specification. When bolts are ordered under the raw material grade (type 304) and not to an ASTM fastener specification, there are no specific requirements other than that they meet the chemical and physical requirements of 304 stainless steel and... Read more

Substituting High Strength Nuts

Can an A194 grade 2H nut be substituted for an A563 grade DH nut? If so, does it work the other way around... Can an A563 grade DH nut be substituted for an A194 grade 2H nut?

Both ASTM A194 Grade 2H nuts and ASTM A563 grade DH nuts are high strength nuts that undergo a heat treating process required to develop their strength characteristics. However, they are not necessarily interchangeable. An A194 Grade 2H nut can always be substituted for an A563 Grade DH nut. In fact, the ASTM A563 nut... Read more

Calculating Grade 8 Shear Strength

What is the shear strength of Grade 8 bolts?

A common question that we get here at Portland Bolt is in regards to the shear strength of bolts. The shear strength is the value at which the lateral stress on a bolt or screw causes it to fail. It is an important factor to take into consideration when designing structural steel or timber connections.... Read more

Galvanized Bolts and Chased Threads

Can threads be chased after hot-dip galvanizing for proper nut fit?

Absolutely not! Externally threaded fasteners should never be “chased”. During the hot-dip galvanizing process, excess zinc has a tendency to build up in the threaded portion of a fastener. Chasing threads is a term used to describe re-cutting threads after galvanizing to remove this excess zinc gained during the galvanizing process. Chasing threads will not... Read more

SAE Grade 8 markings

What visual markings does a grade 8 piece of all thread rod have that would identify it as being so? Meaning, how can you tell just by looking at a stick that it's grade 8?

Most grade 8 bolts require a permanent marking symbol that is designated by 6 radial lines. However, the SAE J429 specification that covers grade 8 fasteners does not require grade markings for studs (fully threaded rods) or slotted and cross recess head products. Therefore, you will not be able to visually identify a threaded stud... Read more

Thread Engagement

How much thread engagement is recommended, i.e. how many threads should extend beyond the nut?

This is a difficult question to answer. Depending on your application, the answer could be anywhere from 1/2 engagement, up to having two full threads extend beyond the nut. Look at these conflicting answers found in four separate technical publications. Federal Highway Administration, “Guidelines for the Installation, Inspection, Maintenance and Repair of Structural Supports for... Read more

Weight Gained from Galvanizing

How much weight is gained from hot-dip galvanizing bolts?

According to the American Galvanizers Association (AGA) the weight of an item on average will increase about 3.5% from the zinc added during the galvanizing process. However, the AGA goes on to say, “…that figure can vary greatly based on numerous factors. The fabrication’s shape, size, and steel chemistry all play a major role, and... Read more

High Strength Bolts Coatings

What corrosion-resistant coatings are available for high-strength (over 150 ksi) bolts?

Due to hydrogen embrittlement concerns ASTM recommends against hot-dip galvanizing , mechanical deposition, or electroplating with zinc or other metallic coatings on high strength bolts ultimate tensile strengths that exceed 150 ksi. So what are the alternatives to provide corrosion resistance for A490 structural bolts? Protective Coatings ASTM recommends that if a protective coating is... Read more

ASTM and SAE Differences

What are the main difference between ASTM 307 GR.B, ASTM A449, and SAE Grade 5 bolts?

There are two specifying bodies when it comes to fasteners. ASTM (American Society for Testing and Materials) covers primarily bolts and fasteners for construction applications. SAE (Society of Automotive Engineers) covers fasteners for automotive, machinery, and OEM applications. ASTM A307 grade B is made from a low carbon steel and is a relatively low strength... Read more

Bolt Thread Length

Is there a standard thread length for bolts?

Depending on the type of bolt you are using the thread length can vary greatly. There is not an inclusive thread length standard that covers all fasteners. Depending on the applications, manufacturer, and a number of other factors the amount thread may change. It is important to clearly communicate at time of purchase your desired... Read more