Staple
A staple is a two-legged wire fastener driven with a pneumatic tool, used on some pallets instead of nails. Pallet staples come in round or rectangular wire (commonly 14 to 16 gauge), are often adhesive-coated, and under the Uniform Standard need a crown of at least 3/8 in that is not parallel to the grain.
Also called pallet staple, wide-crown staple
Reviewed
How staples are specified
| Field | Typical values |
|---|---|
| Wire | round, or rectangular (thickness x width) |
| Rectangular wire gauges | 14 ga (0.075 x 0.080 in), 15 ga (0.067 x 0.073 in), 16 ga (0.055 x 0.062 in) |
| Crown length | at least 0.375 in (3/8 in) |
| Coating | often adhesive-coated to improve holding |
Rules for using staples
- Crown direction: the crown must not be parallel to the wood grain, to avoid splitting along one grain line
- No mixing: do not combine incompatible fastener types in one connection
- Strength: in the Uniform Standard withdrawal equations, a staple is calculated per leg and doubled, using the wire thickness
Staples vs nails
Staples are fast to drive and suit thin boards and lighter-duty pallets. Most heavy and reusable wood pallets are nailed with helical or annular nails. Since PDS 6.12, staples are drawn realistically on the drawings rather than as dots. See pallet nails.
Questions
- Are staples as strong as nails in pallets?
- It depends on the staple and the joint. Each leg is calculated like a small nail, so a two-leg staple is rated from both legs together; heavy-duty pallets usually use nails.
Related
- Pallet nails: types, sizes and how manyPallet nails are usually 2 to 3 in helical or annular threaded nails, 11 to 12-1/2 gauge. A GMA 48 x 40 uses 84 nails: 2 or 3 per joint by board width.
- Helical nailA helical nail has a spiral thread on its shank that turns as it is driven, resisting pull-out. It is the standard pallet nail for medium and dense hardwoods.
- Annular nailAn annular (ring-shank) nail has rings around its shank that lock into the wood fibers. It is recommended for softwood and low-density hardwood pallets.
- Pallet nail schedule: how many nails a pallet needsHow many nails a pallet needs: 2 per joint for boards up to 5-1/4 in wide, 3 up to 7 in, 4 up to 8 in (Uniform Standard). A 48x40 GMA pallet takes 84 nails.
- StringerA stringer is the continuous beam that runs the length of a stringer pallet under the deckboards. A GMA 48x40 uses three 1-3/8 x 3-1/2 x 48 in stringers.
- Stringer classStringer class is the pallet class whose decks rest on continuous stringers. It is one of two classes in the Uniform Standard and PDS, with block class.
Sources
- Uniform Standard for Wood Pallets (NWPCA, now Woodpack Global), 2012 edition
- Pallet Design System (Woodpack Global)