Technical FAQs

Rebar Threading Issues and Solutions

Is it possible to put threads on rebar?

The answer is yes, however, there are several issues to consider to avoid liability. For this discussion, we will assume a requirement for threaded rebar as follows: #8 x 48″ long A615 grade 60 rebar with 8″ thread one end. What is rebar? Rebar is short for “reinforcing bar” and often used in concrete foundations... Read more

Wrench Openings and Socket Sizing

How do I determine the proper wrench opening or socket size to tighten a specific size of bolt?

Socket sizes and wrench openings for tightening nuts and bolts are determined by the dimension across the flats of either the nut or bolt head. According to the Machinery’s Handbook, 26th edition, “Wrenches are marked with the ‘nominal size of wrench’ which is equal to the basic or maximum width across flats of the corresponding... Read more

Bolt Thread Pitch Series

What are my thread pitch options when ordering bolts?

There are several different thread series available for construction fasteners. Below are the three of the most common thread series utilized in the fastener industry.  Coarse Thread Series Unified National Coarse (UNC) – Coarse threads have fewer threads per axial distance than fine threads and a larger thread form relative to the diameter. Coarse thread... Read more

Cutting Bolts in the Field

Is it acceptable practice to alter a bolt’s length in the field if it is too long?

Altering a bolt’s length or configuration in the field is acceptable as long as it does not change the length originally specified by the designer or engineer. If a bolt is longer than what was originally needed, the bolt can be cut down in the field. How the bolt is cut is important to consider.... Read more

ASTM A325 vs. Grade 5 bolts

What is the difference between Grade 5 and A325 bolts?

While these two bolts are virtually identical in terms of chemical and physical strengths and properties, there are several differences between the two. The Grade 5 specification falls under the Society of Automotive Engineers (SAE) classification system, while A325 is an ASTM specification. ASTM A325 bolts are more commonly specified by engineers for use in... Read more

Stainless Steel Grades

What are the differences between 18-8, type 304, and type 316 stainless steels?

To answer this question, you first need to know some basic information about stainless steel. “Stainless Steel” is the general name for a large family of alloy steels that contain at least 10.5% chromium as part of their composition. At and above this level of chromium, a complex chrome-oxide surface layer forms that prevents further... Read more

Rules for Reusing Bolts

Can a bolt be reused? If so, what grades and in what scenarios?

A bolt that has already been used in a given application may or may not be reused, depending on the grade, application, and recommendation of the “Engineer of Record”. There are a tremendous number of conflicting opinions on this subject, but the only definitive published information we can find on this issue from a reputable... Read more

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

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

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