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Mixed hardwood pallet lumber

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In short

Mixed 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% low-density (class 7). It weighs about 4.37 lb per board foot green including nails, so a GMA-style 48 x 40 pallet comes in around 59 lb.

On this page
  1. What mixed hardwood is
  2. Species classes in the mix
  3. Weight
  4. Strength and typical use
  5. Nails for mixed hardwood
  6. Price assumption in palletdesign.ai
  7. Specifying mixed hardwood

What mixed hardwood is

"Mixed hardwood" means pallet stock sawn from whatever Eastern hardwood logs a mill processes, sorted by density rather than by single species. It is typically sawn into cants and cut to size, and it is a common default for stringer pallets in the eastern US.

On a PDS spec sheet it appears as a lumber mix. A typical published example:

Species class Grade Share
High-density Eastern hardwoods (class 1) Standard &BTR 50%
Medium-density Eastern hardwoods (class 3) Standard &BTR 25%
Low-density Eastern hardwoods (class 7) Standard &BTR 25%

Other published mixes lead with oak (class 21) plus high- and medium-density hardwoods.

Species classes in the mix

Class Examples (Uniform Standard Annex B)
1, high density beech, green and white ash, sweet and yellow birch, black cherry, black locust, elm, hickory, hard and red maple
3, medium density black ash, hackberry, silver and striped maple, magnolia, paper birch, sweetgum, sycamore, tupelo
7, low density basswood, aspen, buckeye, butternut, catalpa, cottonwood, eastern poplar
21, Eastern oaks red oak, white oak

Classes 1, 3 and 21 are in the Uniform Standard's medium/high-density sort group; class 7 is in the low-density group. That difference matters in two places:

  • Buyer rules. Home Depot is documented as excluding class 7, so a 50/25/25 mix with low-density hardwood would not qualify. See Home Depot pallet requirements.
  • Repairs. The Uniform Standard's repair rules restrict low-density classes, including class 7, to interior deckboards.

Weight

Condition lb per board foot (incl. nails) GMA-style 48 x 40 (13.5 bd ft)
Green, at manufacture 4.37 about 59 lb
Kiln dried to 19% (engine factor) 2.91 about 39 lb
12% moisture (published PDS sheet) 2.74 about 37 lb

The green figure is calibrated against a published PDS sheet for a 50/25/25 mix. Green hardwood is heavy, and it loses weight as it dries in service. See pallet weight.

Strength and typical use

Mixed hardwood is the workhorse for GMA-style 48 x 40 pallets, grocery and general freight, and many custom industrial pallets. Hardwood pallet stringers are often 1-1/4 or 1-3/8 x 3-1/2 in actual size, narrower than the 1-1/2 in of softwood 2x4s.

palletdesign.ai uses an allowable bending stress of 1,100 psi for mixed hardwood, the conservative allowable value it uses for indicative checks. The indicative check uses it to catch clearly weak designs, such as a GMA-style 48 x 40 racked on too long a span. It is a deliberately conservative screen, not a rating; ratings come from a PDS analysis or physical testing. As an illustration, a published PDS example rated a similar GMA-style pallet at about 1,558 lb racked across its length.

Nails for mixed hardwood

Helically threaded nails are recommended for medium- and high-density hardwoods and dominate automated pallet assembly, so they suit most mixed hardwood. The PDS GMA example uses a 2-1/4 in x 0.112 in (11-1/2 gauge) helical nail. If the mix is mostly low-density hardwood, annularly threaded nails are the usual recommendation. See pallet nails.

Price assumption in palletdesign.ai

The engine's default is $700 per thousand board feet (MBF) for green, standard-grade mixed hardwood, or $0.70 per board foot. For the 13.5 board foot GMA-style pallet that is about $9.45 of lumber, before nails, labor and any heat treatment. Kiln drying adds 15% and premium grade 20%. This is palletdesign.ai's default cost assumption, not a market quote. Lumber prices move, so use your mill's current price for a real quote.

Specifying mixed hardwood

A clear spec states the species classes and shares (or excluded classes), the grade, and the moisture condition, for example: "Mixed Eastern hardwoods, classes 1 and 3 only, Standard &BTR, green". If you need weight or moisture control, specify kiln drying. See kiln-dried vs heat-treated.

Questions

What species are in mixed hardwood pallets?
Eastern hardwoods sorted by density: high-density species such as ash, beech, birch, hickory and hard maple; medium-density such as soft maple, sweetgum and sycamore; and sometimes low-density species such as aspen, basswood and poplar.
How much does a mixed hardwood pallet weigh?
A GMA-style 48 x 40 in mixed hardwood pallet weighs about 59 lb when built green and about 37 to 39 lb once dried.
What nails should be used in hardwood pallets?
Helically threaded nails are recommended for medium- and high-density hardwoods. Annular (ring shank) nails suit low-density hardwoods.

Sources