Parts of a pallet: deckboards, stringers, blocks and fasteners

Every wood pallet is built from the same short list of parts: deckboards, a spacer layer, and fasteners. What changes between designs is whether the spacer layer is continuous stringers or separate blocks, how many boards there are, and how thick they are. This guide names each part, says what it does, and gives typical sizes. Terms follow the Uniform Standard for Wood Pallets and the Pallet Design System (PDS) conventions most North American manufacturers use.

#Stringer pallet parts at a glance

A stringer pallet has three component groups: the top deck, the stringers and the bottom deck. The 48 × 40 GMA-style pallet is the reference example.

These are actual dimensions, as specified on a spec sheet. Pallet stock is cut to size, so a "1 × 6" deckboard is often 5/8 in or 3/4 in thick, not the 3/4 in of a dimension-lumber 1 × 6.

#Deckboards

A deckboard is any board in the top or bottom deck, running perpendicular to the stringers. Deckboards are stated as thickness × width × length. On a stringer pallet, the deckboard length equals the pallet width.

#Top deck

The top deck carries the load. Common deckboard thicknesses are 1/2, 5/8, 11/16, 3/4 and 7/8 in (13 to 22 mm). Widths are usually 3-1/2, 4, 5-1/2 or 6 in. The gaps between boards are the deck spacing. On the GMA-style pallet above, the 7 boards leave six equal gaps of 3-1/4 in.

#Lead boards

The lead board is the outermost deckboard at each end. It takes the hits from forks and pallet jacks, so it is usually wider (5-1/2 in or more) and gets more nails. The Uniform Standard asks for lead boards within 1/4 in of their specified position.

#Bottom deck

The bottom deck spreads the load onto the floor or onto the pallet below in a stack. Stringer pallets usually have 3 to 5 bottom boards. Bottom boards must stay clear of the notches, so interior bottom boards are grouped in the middle of the pallet. A pallet with no bottom deck is a skid (single-face).

#Chamfers

A chamfer is a bevel on the edge of a bottom deckboard so pallet jack wheels can roll up and over it. The Uniform Standard calls for chamfers at least 12 in long, cut at 35 to 45 degrees. They are standard on EUR pallets and common on block pallets.

#Stringers and notches

A stringer is the continuous beam between the top and bottom decks. It is stated as width × height × length. Most 48 × 40 pallets have 3 stringers: two on the edges and one in the center. Heavier or wider pallets use 4 or more.

A notch is a cutout in the bottom edge of the stringer. Two notches per stringer make the pallet partial four-way entry. The Uniform Standard recommends a 9 in long opening about 2 in tall (notch plus bottom deckboard), a flat top of at least 7 in, and a corner radius of 1/2 to 1-1/2 in. Square notches are not acceptable because they split.

#Block pallet parts

A block pallet replaces the stringers with blocks and adds stringerboards.

Blocks are named by position: corner block, edge block and center block. They can be solid wood, laminated, or composite (molded wood fiber). The top deck and stringerboards are often assembled first as a "deck mat" with clinched nails, then nailed to the blocks.

Block pallet bottoms come in three main styles:

• Perimeter base: bottom boards around all four edges, like a picture frame. Used on pooled 48 × 40 block pallets and UK 1200 × 1000 pallets.
• Cruciform: a perimeter plus a cross through the center.
• Unidirectional: bottom boards in one direction only, as on the EUR pallet and the CP1 chemical pallet.

#Fasteners

Most wood pallets are assembled with nails. The common types are helically threaded (screw shank) for dense hardwoods, annularly threaded (ring shank) for softwoods and low-density hardwoods, and plain shank for some mat joints. Staples, screws and bolts appear on some designs.

The Uniform Standard for Wood Pallets (2012 edition, Table 5) sets a minimum number of fasteners per deckboard-to-stringer joint by board width:

On block pallets the minimum is 3 per corner block and 2 per interior block. Check the current edition of the standard before treating these as hard rules. The pallet nails guide covers wire gauge, length and MIBANT quality testing.

#Openings and entry

The open spaces between the decks are the openings. Their height is the entry height. On a stringer pallet with 3-1/2 in stringers the end opening is 3-1/2 in tall, and on the GMA-style design the clear width between stringers is about 17-15/16 in (456 mm). Pallet jacks need to reach the floor, so their wheels must pass through a gap in the bottom deck.

#Overall height

Overall height is the top deckboard thickness plus the stringer (or block and stringerboard) height plus the bottom deckboard thickness. The GMA-style example is 5/8 + 3-1/2 + 5/8 = 4-3/4 in (121 mm). See the pallet height guide for other types.

#Using the right names on a spec

Naming parts consistently prevents quoting errors. A good spec lists, for each component group, the count, thickness, width and length in actual dimensions, the species and grade, and the fastener per joint. The spec sheet guide shows how those fields are laid out. You can open the 48 × 40 template to see each part labeled in 3D and in the parts list.