Glossary
Annular nail
Also called: ring shank nail, annularly threaded nail, ring nail
Reviewed
An annular nail (ring-shank nail) has a series of rings formed around its shank that lock into the wood fibers and resist pull-out. Annular nails are generally recommended for softwoods and low-density hardwoods, and are common in block pallets.
How annular nails are specified
Annular nails share the standard fastener fields (length, wire diameter, head diameter, thread length and crest diameter, MIBANT) plus a ring count. In the Uniform Standard's withdrawal formula, annular threads use a factor of 60 against 22 for helical threads, reflecting how the rings grip.
Where they are used
- Softwood pallets: southern yellow pine, SPF and similar species hold rings well
- Low-density hardwoods: such as poplar and basswood
- Block pallets: a typical wood block pallet uses 3 in annular nails through the stringerboard into the block and 2-1/4 in annular nails on the bottom deck
Annular vs helical
| Annular | Helical | |
|---|---|---|
| Thread | rings | spiral |
| Usually recommended for | softwoods, low-density hardwoods | medium and high-density hardwoods |
| Behavior when driven | goes straight in | rotates |
Both easily beat the Uniform Standard minimum fastener withdrawal characteristic that a plain-shank nail cannot meet. See pallet nails.
Questions
- Are ring-shank nails good for pallets?
- Yes, especially in softwoods and low-density hardwoods, where the rings grip the fibers well.
Sources
- PalletOne: choosing the best pallet nails
- PalletOne: anatomy of the block pallet
- Uniform Standard for Wood Pallets (NWPCA, now Woodpack Global), 2012 edition