Pallet stringers
Stringers are the long members under the deck that run the length of a stringer pallet; the first number in a pallet’s size is their length. Standard US pallets have three or more. In a common 48 x 40 each is nominally 4 inches high and 3 inches wide.
| No. | Member | What it does |
|---|---|---|
| 1 | Top deck boards | Run across the stringers; count and width set the deck coverage. |
| 2 | Lead boards | The deck board on each outside edge, top and bottom. |
| 3 | Notched stringers | Cut-outs in the outside and centre stringers let forks enter from the sides: partial four-way entry. |
| 4 | Bottom deck boards | Placed clear of the notches so the forks can pass. |
What a stringer does
The stringers carry the deck boards and hold the pallet’s shape. When a forklift lifts a pallet from the end, the load hangs from the stringers between the forks and the far end. When the pallet is racked across its length, the stringers bridge the beams. They are the backbone of the pallet.
How many
Three is standard: one under each edge and one in the middle. A fourth, or more, shortens the span of each deck board and adds strength, which suits heavy loads, wide pallets and long ones. On a long pallet such as a 96 x 48, four or more stringers are usual.
Size
A nominal 4 x 3 inch stringer is common in a standard 48 x 40. Taller stringers raise the fork opening and add stiffness; thicker ones add strength. Hardwood stringers carry more than pine of the same size.
Notches
A notch is a cutout in the bottom edge of the stringer that lets forklift forks enter from the side. Notched stringers make a pallet partial four-way. They also remove wood from the most stressed part of the stringer, so a notched pallet carrying a heavy load may need a taller or stronger stringer. See two-way and four-way pallets.
Long stringers
Very long stringers can be hard to source in one piece, so they are sometimes made from two pieces joined. Where they join needs care, especially on a racked pallet.
Stringer or block
A block pallet replaces stringers with blocks and stringer boards. More than 80% of US pallets, by one supplier’s count, are stringer pallets. Stringer vs block compares them.
Stringers and the forklift
When a forklift lifts a stringer pallet from the end, the forks sit between the stringers and the deck boards carry the load to them. The outside stringers take the weight at the edges, the centre stringer at the middle. A pallet lifted on short forks puts more strain on the far ends of the stringers.
Racked stringers
Racked with the stringers spanning the beams, each stringer is a beam carrying its share of the load across the gap. Their height matters most here: a taller stringer is much stiffer than a shorter one of the same width.
Lumber for stringers
Stringers are often hardwood even on pallets with softwood decks, because they carry the most stress and hold the most nails. Knots, splits and wane, missing wood at an edge, weaken a stringer, so stringer stock is chosen with more care than deck stock.
Repairs
On recovered pallets a cracked stringer is often repaired with a plug, a short piece nailed alongside it; plugs can run from 6 to 24 inches long. A new pallet’s stringers are whole.
Specifying stringers
Give the number, length, height and width, the lumber, and whether they are notched. If you don’t know, give the load and handling, and the stringers follow.
Failure signs
A stringer that cracks at a notch, splits along its grain from the end, or sags in a rack is telling you the load or the handling is more than it was drawn for. Forks driven in hard can split the ends of stringers on two-way pallets; chamfered or protected ends help. Replace the build, not just the pallet.
Stringer spacing
On a 48 x 40 with three stringers, the outside two sit flush with the edges and the centre one in the middle. With four, the gaps narrow. The spacing must leave room for the forks you use and, on the bottom deck, for jack wheels.
Stringers on long and wide pallets
As the stringers lengthen, their height usually grows to keep them stiff; as the deck widens, their number grows to keep the boards’ spans short.
Common stringer counts by footprint
Small and medium footprints such as 36 x 36 and 40 x 40 usually have three stringers. A 48 x 40 has three, or four for heavy loads. Wide footprints such as 60 x 48 usually have four, and long ones such as 96 x 48 four or more, sometimes with a spliced or doubled stringer down the middle. A square pallet such as 48 x 48 can be built with its stringers either way; say which direction your forks enter.
Stringer ends
The ends of a stringer face the forks on a two-way pallet and take impacts every time it is lifted. Lead boards help protect them; some builds add a chamfer to the bottom corner so a fork tip slides under instead of striking.
Sound ends matter most
Stringers are cut from solid lumber, pine or hardwood. Hardwood resists crushing and holds nails well; pine is lighter and cheaper. Wane, knots and splits near the ends weaken a stringer exactly where forks hit and where the end boards are nailed, so ask for sound ends and check a few on the first delivery. Hardwood stringers under pine decks are a common mixed build that combines both strengths. A fourth stringer under the middle of a heavy deck shortens every board’s span. Ask for the stringer’s grade in writing, alongside its species, size and moisture, so substitutions show up on paper.
On notched stringers, the notch removes wood from the stringer’s lower edge, so a stringer that is fine plain may need to be taller once notched for a racked load.
Stringers are the backbone, so they deserve a line of their own on every spec. Count, size, timber and notching, written plainly, stop most surprises. When a stringer pallet disappoints, look there first, before blaming the deck, the nails or the forklift driver. Watch especially for diagonal grain, large knots near notches, wane along edges and end checks, the small cracks that open as timber dries. Any of these, sitting where tension peaks, invites an early break under load. Good stock selection avoids them; visual grading rules exist precisely for this purpose.