Helically threaded nail (pallet)
Also called: helical nail, screw shank nail, SS nail, spiral nail
A helically threaded nail has spiral flutes rolled into its shank so it rotates as it is driven, which locks it into the wood. It is the most common pallet nail, recommended for medium- and high-density hardwoods.
In depth: Helical vs annular pallet nails: which to specify
"SS" in a pallet fastener ID, as in "2-1/4 x 11-1/2 Ga. SS", means screw shank, the trade name for a helically threaded nail. The thread gives far better withdrawal resistance than a plain shank, and the nail drives well in dense wood and in automatic nailers.
A typical pallet nail (PDS GMA-style example)
| Field | Value |
|---|---|
| Length | 2.25 in (57 mm) |
| Thread length | 1.25 in (32 mm) |
| Wire diameter | 0.112 in (2.8 mm), 11.5 gauge |
| Thread (crest) diameter | 0.124 in (3.1 mm) |
| Head diameter | 0.280 in (7.1 mm) |
| Flutes / helixes | 4 / 7.5 |
| Thread angle | 60° |
| MIBANT | 36° |
| Withdrawal characteristic (FWC) | 2.58 |
The withdrawal characteristic
The Uniform Standard (2012) Annex F rates thread effectiveness as Cw (FWC) = 1 + 22 × (thread diameter − wire diameter) × (helixes ÷ thread length). For the nail above: 1 + 22 × 0.012 × 6 = 2.58. The minimum Cw is 1.9 for reusable pallets and 1.5 for single-use. A deeper thread (larger crest minus wire difference) raises it.
Why it matters
Joint strength and durability depend heavily on the nail. Helical nails are generally recommended for denser hardwoods, and annular nails for softwoods and low-density hardwoods. See helical vs annular nails.
On a spec sheet
Fastener type "Helically Threaded Nail", plus the full field list above.
Related
- GlossaryAnnularly threaded nail (pallet)An annularly threaded nail, or ring shank nail, has a series of rings rolled into its shank that lock into the wood fibers. It is generally recommended for low-density hardwoods and most softwoods.
- GlossaryThread angle (helical pallet nails)Thread angle is the angle of the spiral flutes on a helically threaded nail. Pallet nails typically have thread angles of about 57 to 69°, and together with the flute count and thread diameter it sets how many turns the thread makes.
- GlossaryNail (pallet fastener)A nail is the standard fastener for wood pallets, driven through deckboards into stringers or blocks. Pallet nails are specified by shank type (helical, annular or plain), length, wire diameter, head diameter and bending strength.
- ComparisonsHelical vs annular pallet nails: which to specifyChoose helically threaded (screw shank) nails for medium- and high-density hardwoods and automated nailing; they turn as they drive and resist bending and splitting. Choose annularly threaded (ring shank) nails for low-density hardwoods and most softwoods, where rings grip best.
- GuidesPallet nails and fasteners: types, sizes, MIBANT and nail countsMost wood pallets use threaded nails: helical (screw shank) for dense hardwoods, annular (ring shank) for softwoods. A typical deck nail is 2-1/4 in long with 0.112–0.120 in (11.5–11 gauge) wire. The Uniform Standard requires at least 2 nails per joint on boards up to 5-1/4 in wide and 3 on wider ones.
More in Fasteners
- GlossaryClinched nail (pallet)A clinched nail is driven all the way through the parts it joins and has its protruding tip bent over flat. Block-pallet deck mats (deckboards plus stringerboards) are commonly assembled with clinched nails.
- GlossaryMIBANT (nail bend test)MIBANT (Morgan Impact Bend Angle Nail Tester) is an impact-bend test for nail stiffness, run under ASTM F680. A weight strikes a clamped nail and the resulting bend angle is recorded; a lower angle means a stiffer, better nail.
- GlossaryNail head diameter (pallet nails)Nail head diameter is the width of a nail's head. It sets how well the nail resists pulling through the deckboard; the Uniform Standard requires the head to be at least 2.25 times the wire diameter for reusable pallets.
- GlossaryNailing pattern (pallet)A nailing pattern is the number and position of fasteners at each joint of a pallet. The Uniform Standard sets minimums by deckboard width: 2 fasteners per joint for boards up to 5-1/4 in wide and 3 for 5-1/4 to 7 in.
- GlossaryPlain shank nail (pallet)A plain shank nail has a smooth shank with no threads. It has the lowest withdrawal resistance of pallet nails, so on pallets it is mainly used where it is clinched, such as block-pallet deck mats.
- GlossaryScrew (pallet fastener)A screw is a threaded fastener turned into the wood rather than driven. On pallets, deck screws, lag screws and washer-head self-drilling screws are used for heavy skids, plastic lumber pallets and designs that must be taken apart or repaired.
Last reviewed 2026-09-24. 251 words.