Bolt Industry FAQs

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

Dimensioned Closed Eye Bolt

Bent Bolt Dimensions

What Dimensional Specification Covers Bent Bolts?

ASME, a global standards organization, provides dimensional guidelines and dimensional tolerances for a wide variety of fasteners and related items. Bent bolts, such as 90-degree bend anchor bolts, U-bolts, and eye bolts, fall under ASME B18.31.5. ASME B18.31.5 provides information regarding tolerances and quality, and their drawings also indicate where the bolts should be measured... Read more

Unthreaded Shank

What do you call the unthreaded shank of a bolt?

The unthreaded portion of a headed bolt is called the grip. The length of all headed bolts (except countersunk head bolts) are measured from underneath the head to the end of the threads. The overall bolt length is made up of thread length plus grip length.

Certified Mill Test Reports

What is a “CMTR”?

The acronym CMTR stands for, “Certified Mill Test Report” or “Certified Material Test Reports.”  As a manufacturer, it is imperative that we are using the correct raw material when manufacturing a given part, whether it is a bolt or fabricated steel plate.  A CMTR is provided by the raw material producer (mill), which is a... Read more

Stainless Yield & Tensile Strength

What are the strength and yield values for stainless steel bolts?

Typically when bolts are ordered, they are called out by a specific ASTM or SAE grade. Stainless steel bolts are a bit different though, as they are commercially available and regularly ordered simply by the material itself, most commonly 316 or 304 stainless steel. Unlike bolts that fall under ASTM specifications, there are no specific... Read more

RCSC

What is the RCSC?

RCSC is the Research Council on Structural Connections. It is a non-profit, volunteer organization, comprised of over 85 leading experts in the fields of structural steel connection design, engineering, fabrication, erection and bolting. Its goal is to support research and gain knowledge to publish standards in structural steel connections.

Heavy Square Head Bolts and Nuts

Are heavy square head bolts and heavy square nuts available?

According to ASME, a global standards organization which provides manufacturers with guidelines and tolerances for producing parts, there are no listed dimensions to manufacture heavy square head bolts. However, ASME does provide dimensions for heavy square nuts. ASME B18.2.1 This standard covers the dimensional requirements for nine product types of inch series bolts and screws... Read more

Clevis Numbers

Why are clevises called out by a number?

Clevises are a component of tie rod assemblies that rods thread into. Unlike most other female threaded components such as nuts or turnbuckles, calling out a clevis size by the diameter of rod being threaded into it is not the correct way to reference it. Clevises are called out by a number, ranging from a... Read more

Bolt Length

Does the length measurement of a bolt include the head?

In most cases, when specifying the length of a headed bolt, the thickness of the bolt head is not included. For instance, if you were to order a ¾” x 24” hex head bolt, the bolt would measure 24” from under the head. One exception to this method of measurement is countersunk bolts. When specifying... Read more

Clevis

High Strength Clevises & Turnbuckles

Are high strength clevises and turnbuckles available?

High strength clevises can be provided in instances where smaller clevises are needed while keeping a higher safe working load. High strength clevises are also used to develop the full capacity of high strength threaded rods. Since high strength clevises are not readily available in the marketplace, these items and can add significate lead time... Read more