An Open Frame or a Sealed Enclosure — That Is the Choice.
A crate is an open, ribbed timber frame: load-bearing members, diagonal bracing and partial sheathing that hold and protect the cargo while leaving gaps. It is lighter, cheaper and lets a forklift and the eye reach the contents. A box (or case) is a fully sheathed, closed enclosure — six solid sides — that shuts the cargo away from rain, spray, dust and casual theft. Both can be built to carry the same weight; the difference is whether the cargo is exposed or enclosed.
So the decision is rarely about strength alone. It is about what the cargo cannot tolerate. A weatherproof, robust steel fabrication may travel happily in an open crate. A sensitive machine with electronics, bright machined surfaces or a resale-grade finish needs the closed box — and, inside it, a sealed moisture barrier, because even a closed box is not airtight. Get the enclosure right first, then size the timber to the weight.