Pallet lumber and fasteners
The wood and the nails. Species, grade and moisture set a pallet's weight, strength and cost; the nail sets how long it lasts. 16 pages.
Lumber species
- Pallet lumberPallet lumber is specified by three things: species class (from Annex B of the Uniform Standard), grade, and moisture content at manufacture. In North America the common choices are mixed…
- Mixed hardwood pallet lumberMixed hardwood is the most common pallet lumber in the eastern US: a blend of Eastern hardwood species classes, often 50% high-density (class 1), 25% medium-density (class 3) and 25%…
- Oak pallet lumberOak (red and white oak, Uniform Standard species class 21) is one of the densest common pallet woods. palletdesign.ai assumes about 5.25 lb per board foot green and 3.9 lb kiln dried,…
- Southern yellow pine (SYP) pallet lumberSouthern yellow pine (SYP) is the dense softwood group of loblolly, longleaf, shortleaf and slash pine, species class 22 in the Uniform Standard. palletdesign.ai assumes 4.45 lb per board…
- SPF (spruce-pine-fir) pallet lumberSPF (spruce-pine-fir) is Uniform Standard species class 13, a low-density softwood group. It is the lightest of palletdesign.ai's five species at about 3.24 lb per board foot green and 2.3…
- Douglas fir pallet lumberDouglas fir is a western softwood classed with larch as Uniform Standard species class 11, in the medium/high-density sort group. palletdesign.ai assumes about 3.9 lb per board foot green…
- Hem-Fir pallet lumberHem-fir is a western softwood lumber group (western hemlock with true firs) that the Uniform Standard for Wood Pallets classes as species class 12, in the low-density sort group. For…
Lumber properties
- Pallet lumber gradesPallet lumber grades limit defects such as knots, wane, splits, decay and slope of grain. The Uniform Standard sets two minimum quality levels, reusable (about PDS Standard grade) and…
- Pallet lumber moisture contentMoisture content (MC) is the weight of water in wood as a percentage of its dry weight. Pallets are built either green or kiln dried, commonly to 19% (KD19). Drying cuts weight (a…
- Kiln-dried vs heat-treated palletsKiln drying (KD) removes moisture from lumber to a target, commonly 19%, to cut weight, shrinkage and mold. Heat treatment (HT) is the ISPM 15 phytosanitary treatment, holding the wood…
- Nominal vs actual lumber sizes for palletsPallet drawings and PDS specs always use actual dimensions at manufacture, not nominal lumber sizes. A nominal softwood 2x4 is 1-1/2 x 3-1/2 in, a 1x4 is 3/4 x 3-1/2 in and a 1x6 is 3/4 x…
- Recycled pallet lumber and remanufactured palletsRecycled pallet lumber is reclaimed from dismantled pallets and reused to repair pallets or build remanufactured and combo pallets. The Uniform Standard classes these as Remanufactured or…
Fasteners
- Pallet nailsMost wood pallets are assembled with threaded nails: helically threaded for medium- and high-density hardwoods, annularly threaded (ring shank) for low-density hardwoods and most…
- Pallet nail qualityPallet nail quality comes down to stiffness and grip. Stiffness is measured by the MIBANT bend angle (lower is better; 8 to 24 degrees is rated excellent), and grip by the fastener…
Panels and blocks
- Plywood and OSB pallet decksPlywood and OSB panels are used as solid pallet decks for small, point or unstable loads. Under the Uniform Standard they must be grade-stamped PS 1, PS 2 or PRP-108 panels with exterior…
- Presswood (wood-composite) pallet blocksPresswood blocks are wood-composite pallet blocks made from wood fiber and resin under heat and pressure. The Uniform Standard requires a density of 36.9 to 42.1 lb per cubic foot (591 to…