News & Insights

Three Ways Increasing the L/D Ratio Improves Reliability of Dynamically Loaded Bolt Joints

Article
September 7, 2021
<p>During design reviews, experienced engineers may point out that a larger ratio of clamped length to bolt diameter (L/D) improves the reliability of dynamically loaded bolted joints, but they may not give a satisfactory explanation for this advice. This article explains three benefits of designing dynamically loaded bolted joints with a sufficiently large L/D ratio.</p>

Simple Test Technique to Determine Type of Fastener Loosening

Article
January 25, 2021
<p>Bolted joints are extremely reliable through the life of the product, as long as the bolt remains tight. Unfortunately, bolts often loosen when placed in service, and they can become a source of reliability problems. Understanding whether a bolt loosened due to self-loosening, relaxation or a combination of both is critical for making the right design changes or choosing the best thread locking method. Fortunately, a simple torque stripe can used to detect if a bolt loosened and if so, the type of loosening that occurred.</p>

A Tale of Two Solar Racking System Fasteners: Threaded vs. Lockbolt

Case Study
April 10, 2020

The Use of Two Nuts to Prevent Self-Loosening Intro

Article
November 11, 2019

What Should Be Tightened—the Nut or the Bolt Head?

Article
June 12, 2019
<p>The question is often asked as to whether the nut or the bolt head should be tightened. Although at first blush a seemingly unimportant distinction, the choice you make in tightening the nut or bolt matters and can affect the final preload. In this article, Dr. Bill Eccles explains the parameters which affect preload variation and the importance of providing detailed instructions to the assemblers.</p>

Self-Loosening of Threaded Fasteners

Article
April 15, 2019

Failure of an M24 Engine Mounting Bolt

Case Study
February 1, 2019

Preload Relaxation in Aluminum PV Racking System Fasteners

Article
September 25, 2018