By: Terri Shadrix
How do manufacturers ensure that the metal cam buckle or ratchet hardware from their supplier will hold Webbing tight at peak load in high-strain applications such as tent or tarp tie downs? The short answer is metallurgy.
Metal qualities differ, and the process of shaping raw metal into hardware can vary from factory to factory. Exact specifications may not matter if budget allows you to over-engineer by using a heavier gauge metal cam buckle or ratchet handle for example, but that can add unnecessary costs.
We asked our Metal Hardware Team to outline the top considerations in choosing the right metal webbing hardware for applications such as heavy duty tie down straps. Here’s what they had to say:
Overview of Metal Strength
What makes metal strong? Although the word "strong" is ambiguous, properties of "strength" such as malleability and ductility are characteristic of some metals because of metallic bonding. However, not all metals are "strong." In fact, sodium metal is so soft it can be cut with a knife.
A related question is what makes materials stiff (strength is resistance to permanent deformation, stiffness is resistance to elastic, or recoverable, deformation). Stiffness is strongly coupled to the interatomic bond strength. So is density and melting temperature, and the element-to-element trend for these three material properties is similar.
Options in Metal Hardware for Webbing
Which metal to consider depends entirely on the application. Below are common material categories and their advantages and disadvantages.
What Strength Does Your Application Need?
One of the most common uses we see is a metal cam buckle holding nylon webbing straps securely in place at the corner of a tent, or at tie-down points of a truckers tarp. In these examples we first look to the immediate strain from tightening the strap either by ratchet or pulling the strap through the cam by hand. Where the use is outdoors, you’ll need to add in other strains from natural winds or wind resistance from driving into load calculations.
From Light-Duty to Heavy-Duty:
• Light-weight to mid-weight applications can use wire-formed, stamped or die-cast metal hardware to achieve adequate strength.
• Manufacturers of mid to heavy-duty tents and tarps narrow their focus to high strength materials such as steel or stainless steel.
Strength of wire formed items such as d-ring, o-ring, triangles and loops can be dramatically increased with strong welds and gauge. (see our Metal Gauge Chart) Stamped items can be made stronger by increasing the thickness of the of the sheet being stamped. Complex webbing hardware such as ratchet straps are manufactured and tested to a specified strength.
Remember to Account for Exposures
Higher-temperatures settings can have an impact on the stiffness of some metals. And exposures to humidity and rain can eventually cause rust in steel and other metals thus shortening their useful life.
Pro Tip: To extend the life of tie downs keep them dry and store out of the elements when not in use.
The Bottom Line
Selecting metal webbing hardware engineered to handle both strains and exposures, and one that is matched to fabric durability, will help ensure the overall assembly lasts the full intended life-span.
We invite manufactures and distributors to take a look at this selection of our most popular DirecTex Metal Hardware. If you don’t see it, DirecTex can get it - just contact us for a quote on special stock or custom item orders. Or if you have questions, feel free to Live Chat with one of our team