Crating

A crate is the highest level of protection you can give a shipment, and it is often what makes fragile or high-value freight insurable in the first place. It is also the packaging most likely to be built wrong, because a wooden box that looks solid is not necessarily a crate.

When to crate

Reach for a crate when any of these is true:

• The product is fragile and a knock from adjacent freight would damage it. Glass, ceramics, instruments, screens, castings with brittle features.
• The finish matters. Painted, polished, plated, or coated surfaces get abraded by contact, and stretch film does nothing to prevent it.
• The value is high enough that a claim would hurt, or your insurer requires it.
• The shape is awkward. Protruding parts, an unstable center of gravity, or nothing flat to sit on.
• It is machinery. Anything with shafts, linkages, control panels, or fluid connections benefits from a rigid shell.

A crate can be fully enclosed or built as a skeletal frame, depending on what the freight needs. Skeletal is lighter and cheaper. Enclosed adds protection from dust, water, and prying.

The parts of a skeletal crate

What a crate has to include

• Three-way locking corners. Every corner joint has to lock in all three directions. This is a requirement rather than a preference, and it is the main thing that keeps a crate intact through handling.
• No opening larger than 25 inches. On a skeletal crate, no side, end, or top opening may exceed 25 inches in length, width, height, or across the diagonal. Larger openings let adjacent freight and fork tines reach the product.
• Diagonals between 30 and 60 degrees to the adjacent strut or header. Outside that range the brace stops adding meaningful rigidity.
• Everything inside blocked, braced, and cushioned. A rigid shell around a product that can move inside it is not protection. This is not optional.
• Struts landing on extended bottom deck boards, so they never drag on the ground.
• Headers on the outside face, so the crate slides past adjacent freight instead of catching on it.

Long, tall, and enclosed crates

Long crates, over 80 inches. Same rules as long pallets. Design for access on all sides, include chamfered runner boards so the crate can be slid safely, leave at least 28 inches between those runners for a pallet jack, and use 1.5 inch bottom deck boards between the stringers and the runners. Keep every diagonal within the 30 to 60 degree range. If the crate is also too wide for a pallet jack, see the long-pallet guidance in Pallets.

Tall crates. Add extra header boards along the length or the width. Watch the height-to-base ratio from What your freight goes through, because a tall crate is still top-heavy freight.

Enclosed crates. Plywood and OSB behave nothing like solid wood, and most enclosed crate failures come from treating them as if they do:

• Support every plywood or OSB edge with solid wood. An unsupported panel edge is a hinge.
• Solid wood must support solid wood at the top. If a solid board bears only on a panel, a load from above will punch the board straight through it.
• Fasteners must end in solid wood. Drive them through the panel and into the framing, never into the panel alone.
• Use the right panel grade. Structural 1 rated sheathing gives the best cross-panel strength, and Exterior or Exposure 1 grades handle moisture.
• Match the span rating to the load, and fasten roughly every 6 inches along every panel edge.

Wood grades, fastener sizes, and fastening patterns are the same as for pallets. See the wood and fasteners section of Pallets.

Before you build one yourself

Crating well is a skill, and a badly built crate can be worse than a well-wrapped pallet because it gives false confidence. If you are crating something valuable for the first time, a commercial crating shop is usually the better call, and many will build to a drawing you can reuse.

If you are designing your own packaging to ship repeatedly, it is worth having the design evaluated before you commit to it. Testing laboratories accredited by ISTA, ASTM, or the CCSB will run a package through a standard sequence and show you where it fails.