NEWSLETTER

Castellated nuts, often called a castle nuts, employ cotter pins as a locking mechanism. We will walk through two key points that render many castle nut bolted joints ineffective and unreliable. 1. The castle nut must be in a certain

Let's compare a typical assembly using one nut and a bolt against the use of double nuts. Single Nut Figure 1 When the nut is rotated in the counterclockwise direction, it moves toward the bolt head. Each full rotation (360°) moves the

Security Locknut Last time, we discussed why you may not need a locknut if the joint is properly designed and assembled. But, in the real world, on critical applications, this is often difficult to consistently achieve. In these common situations, a

You shouldn’t need a locknut if the bolted joint is properly designed and assembled. This means it’s designed to hold the working load, is tightened to the specified value, and the preload force is maintained. This seems simple enough. If

The relationship between input torque and tension is the governing principle behind a well-designed bolted joint. Often, calculated values are not reciprocated in field applications. To determine the tension (also known as preload, clamp force, or clamp load), a Skidmore-Wilhelm

It is well understood that a fastener will fail if it is loaded above its capacity, as shown in example #1 below. What is less obvious is a fastener will also fail if it is loaded below its capacity but

Hint: not as much as you think. To answer this question, let’s start with an example of a fastener assembly with a 3/4" x 10 Grade 5 bolt and nut and a 2” clamp distance, as shown in figure 1. Figure 1 For

Answer: a very small but important amount. In previous posts we discussed how a bolted joint works, how clamp force is calculated, and how to determine torque required to achieve the clamp force. This month we’ll present more details about the

We are often asked what torque value should be used with a specific nut/bolt assembly. First, it’s helpful to understand that torque is a rotational force that is equal to a linear force times the distance of that force from

Clamp force is what holds a bolted joint together. Published charts are available for determining clamp force but we’ve found it’s often useful to understand how these numbers are calculated. Image from smartbolts.com Bolt and nut ratings can be confusing. Bolts are