Crate spec ticket
| Members | Plywood panels, edge cleats, corner cleats, base |
|---|---|
| Base | Skid or cleated floor with runners |
| Joins | Nailed or screwed through cleats |
| Assembly | Panels built flat, then boxed |
| Reference | ASTM D6251 for panelboard boxes |
| Quote needs | Inside dimensions, gross weight, destination |
How a cleated panel crate goes together
Each wall, end and lid is a panel: a sheet of plywood with cleats fastened along its edges. The cleats do two jobs. They stiffen the sheet, which would otherwise flex, and they give the next panel something solid to be nailed or screwed into at the joint.
Panels are built flat on a bench, which is quick and accurate, then stood up around the load and tied at the corners. The floor panel rests on runners or a skid so a fork can lift it. The result is a closed box in which the cleats, not a continuous stud frame, carry the structure.
Which loads fit
Cleated plywood is a good match for instruments, small machine assemblies, enclosures, spare parts kits and packaged electrical goods. The load is usually modest in weight and benefits from a smooth, clean interior. If the item can be lifted by two people, a cleated box is often more than enough.
ASTM D6251 covers wood-cleated panelboard boxes, and its name hints at where the construction is strongest: panelboard boxes for moderate gross weights. For heavy machinery on its own feet we move up to a sheathed crate with a full stud frame.
Tare and cube
Panels use less lumber than a full frame, so a cleated crate weighs less than a sheathed one built around the same inside dimensions. Cleats are small in section, which keeps the walls thin and the outside dimensions close to the inside ones. That helps both parcel-sized and air shipments, where size and weight set the price.
The saving is real but it has limits. A thin panel is only as strong as its cleats and fasteners, so increasing the load usually means thicker sheet, closer cleats or a switch of construction, not just more nails.
Export and the stamp
Plywood is exempt from ISPM 15 on NELMA's list. A crate built wholly from plywood panels with plywood-based floor members needs no treatment stamp. The cleats, though, are usually solid wood, and so are any runners or skid boards under the floor.
Where those solid parts are present they have to be heat-treated and stamped, with the mark on a minimum of two opposite sides. We say on the quote exactly which members are lumber and which are sheet, so the paperwork matches the crate. Whether the destination wants the mark at all is a question for APHIS and the receiving country's plant-protection authority.
Weak points
Corners are the weak point. A panel joined to its neighbour through one thin cleat will split if the crate is dropped on an edge. Fasteners that run into end grain hold poorly, and thin plywood can tear around nail heads when a forklift scrapes the wall.
We run corner cleats on the vertical edges, stagger fasteners and keep nails away from sheet edges. Where a part inside is heavy for its footprint, we add a bolted base plate or blocking and bracing to the floor, so the weight goes into the runners instead of the box walls.
Cleated plywood versus solid lumber
The alternative at the other end of the strength scale is the solid-lumber crate, built from boards instead of panels. Lumber boxes take more punishment and handle high point loads, but weigh more and always carry the export stamp. A cleated plywood crate is closed, clean and light, and a good fit if the load is not trying to break out of it.
If you are undecided, the weight and the way the item is lifted usually settle it. Tell us both.
Finish, marking and small-lot practice
The smooth faces of a cleated panel crate take stencils and labels well. Handling marks go on at least two adjacent faces: a pictogram set, a gross weight, a crate number and a destination block. A label on the lid alone vanishes the moment another box is stacked on top.
Small lots suit this build because panels can be cut and cleated in batches, with the box assembled as each load arrives. Instruments often arrive in their own foam and carton, and the crate then serves as outer packaging. Leave a few inches of void filled with foam or paper, never loose chips, which settle and leave the load free to rattle.
Giving us the numbers
Send the inside dimensions in inches, the gross weight in pounds, the destination country, quantity and the date needed. A load measuring 30 x 24 x 20 in is a fair example of the scale we mean. Say whether the crate will be opened and closed more than once, because that decides screws against nails and whether the lid gets hardware.
Questions buyers ask
Is a cleated plywood crate strong enough for machinery?
For small and moderate machines, yes. For heavy machines that stand on their own feet we build a sheathed crate with a full frame and a skid.
Do the cleats need an IPPC stamp?
If the cleats are solid wood, yes for export where treated wood is required. The plywood itself is exempt under NELMA's list.
Can it be opened and closed again?
Yes. Screws and a removable lid panel make it reusable, and we note that on the spec.
What does ASTM D6251 have to do with it?
It is the standard that describes wood-cleated panelboard boxes, so it is the reference name for this construction on a drawing.