Stringer pallets: three timbers under the deck

How it is built

Stringers run the length of the pallet, usually three of them. Deck boards go across the top and, on most, the bottom. The notched version has half-moon cuts in the stringers that let forks enter from the sides as well as the ends.

Strengths and weak points

Cost

The simplest and usually cheapest wood pallet to build and repair.

Repair

Cracked boards are replaced; cracked stringers are fixed with a plug, a short board nailed beside the crack.

Weak point

A cracked stringer unrepaired makes the pallet a core.

Entry

Two sides as standard; four with notched stringers.

The 48 x 40 standard

The standard GMA pallet is a stringer pallet, and most of what moves through Orlando docks is the same build. The 48 x 40 page has the numbers.

Reading a stack

In a sorted stack, stringer pallets show their ends: three timbers and a deck line. Repaired ones show a newer board or a plug beside a stringer, which is how you can tell Grade B from Grade A at a glance.

The cheapest pallet, and why it persists

Reference works describe stringer pallets as among the oldest designs and the simplest to build, which is why softwood versions are often treated as expendable at the end of a single trip. They suit loads that go out once and do not return. The same simplicity makes them easy to repair: a deck board is replaced in minutes, and a stringer can be mended with a companion timber.

Ways a stringer pallet fails

• A stringer splits where a notch has taken wood away.
• A nail pulls out of a deck board because the pallet was lifted by the wrong side.
• A forklift tine pushes through a bottom board when forks are driven in at an angle.
• Moisture swells the ends of the boards and loosens the fasteners.

Measurements from the stringer

In a pallet measurement the first number is the stringer length. A 48 x 40 stringer pallet has three stringers 48 inches long, which are the supports that rest on a rack beam or the floor. Heavy-duty versions use three stringers of about 4 by 3 inches in section, which is where weight above 100 pounds comes from. Because a stringer carries the load along its length, a crack across it is serious, and a crack along it can sometimes be repaired with a companion timber.

Lumber sizes in a stringer pallet

Lumber is sold under nominal sizes, and the real sizes are smaller. A nominal 2 by 4 stringer measures 1.5 by 3.5 inches. A nominal 1 by 4 deck board is about three-quarters of an inch thick and 3.5 inches wide, and a nominal 1 by 6 board is about 5.5 inches wide. Turning a 2 by 4 on its edge gives a fork opening of 3.5 inches, which is why a standard stringer pallet stands roughly five and a half inches tall.

Nails that hold

A smooth-shank nail can back out as wood dries and swells. Spiral or ring-shank pallet nails grip the fibre and hold better, and most pallet builders use them for deck boards. A repaired pallet with plain nails driven into old holes is weaker than the original, which is part of why a repaired pallet is graded below one that has never been repaired.

Stringer pallets in racks

A stringer pallet is stable on a rack when the stringers run across the beams, so each stringer is carried on two supports. If the pallet is turned so the stringers run along the beams, the deck boards sit on the beams and can bow under a heavy load. Rack operators therefore specify which way a stringer pallet must face when it is slid into a bay.