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Originally Posted On: https://www.palletone.com/the-anatomy-of-a-wooden-stringer-pallet-components-and-fasteners/

In today’s logistics and supply chain management, wooden pallets are ubiquitous, the sturdy and reliable workhorses of physical goods distribution. For many of us, they are invisible. Supply chain operators have other things to think about. 

Not surprisingly, few pause to consider the design and construction details that go into these essential platforms of modern commerce. In fact, wooden pallets are highly engineered marvels created to move your loads cost-effectively, safely, and with the lowest environmental impact possible. 

This article delves into the anatomy of the wooden stringer pallet, focusing on the basic ingredients: the wood components and the fasteners that hold them together. They are comprised of four component groupings: the top deck, the stringers, the bottom deck, and fasteners. Let’s take a closer look at each of these elements.

Top Deck Boards

The top deck boards are the flat pieces of wood that form the top of the pallet. Typically they are ⅜”, ½”, ⅝” or thicker, and 3 ½” or 5 ½” in width, but all of these dimensions can vary, depending upon the use case and material availability. Thicker material or more dense wood species can help improve pallet performance where needed. 

Don’t forget about deck board placement. The corners of the boxes are the strongest part of the box structure and are designed to carry the weight of the box and its contents. Aligning these corners with the deck boards means that the boxes can effectively utilize their structural strength to support the weight of the unit load. Another important deck board design component is the butting of lead or end boards. Pallet lead boards must stand the test of being impacted by forklifts. Butting two 6” lead boards can result in up to a 38% improvement in pallet durability, according to Virginia Tech.

Stringers

Running perpendicular to the deck boards are the stringers. These vertical members provide the main support structure for the pallet. Stringers can be likened to the spine of the pallet, distributing the load evenly across the structure and ensuring the pallet’s stability and strength. The standard pallet design usually includes three stringers, but this can be adjusted based on the intended load capacity. Adding more stringers effectively shortens the span between them, thereby reducing top deck deflection under load. Likewise, by using a wing pallet – moving the stringers away from the edge of the load toward the center – you can reduce span and improve pallet strength without adding extra material.

Base or Bottom Deck

The bottom deck of a pallet provides additional stability and functionality. Bottom deck design is an essential consideration for pallets that must be carried on conveyors or for pallets that will be racked or stacked on top of other product. 

Stringer pallets typically have a unidirectional base, with all the deck boards oriented in the same direction. For example, the GMA pallet has five unidirectional bottom boards. When designing a pallet that must be conveyed, having the boards run perpendicular to the rollers will provide smooth conveyance as opposed to bottom boards parallel to the rollers. This orientation can result in a bumpy ride if rollers are too far apart. Where unit loads are to be stacked, having more bottom deck board coverage helps distribute weight more uniformly to prevent product damage.

Now, let’s talk about the fasteners, the unsung heroes that hold these components together.

Fasteners

Fasteners are critical to the structural integrity of the pallet. The choice of nail type, size, stiffness, and application method can significantly influence the pallet’s strength and durability. They include driven nails, staples, bolts, wood screws, and lag screws. Most pallets utilize one of two types of nails, including helically-threaded or drive-screw nails and annularly threaded or ring-shanked nails. 

Helically threaded nails feature continuous spiral threads along the shank. Annularly threaded nails come with numerous rings along the shank that help grip the wood and prevent nail withdrawal. Of the pair, helically-threaded or drive-screw nails are the most popular choice for automated pallet assembly. Both types, however, are widely used by pallet manufacturers.  

Pallets designed for heavier loads may also use bolts or screws in addition to nails for added strength.

So there we have it. The wooden stringer pallet seems simple: top deck, stringers, bottom deck, plus fasteners. But the magic is in selecting and combining those ingredients to provide the most cost-effective and sustainable option for unit load and for your supply chain. Contact PalletOne to help you connect the dots.