Thread angle (helical pallet nails)
Also called: helix angle, flute angle
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.
In depth: Pallet nails and fasteners: types, sizes, MIBANT and nail counts
Thread angle is one of the geometry fields that describe a helically threaded nail. It is measured with a thread gauge or from the rolled thread, and it appears on PDS fastener tables and nail supplier spec sheets.
Typical values
| Nail | Thread angle |
|---|---|
| PDS GMA-style example, 2-1/4 × 0.112 in | 60° |
| Uniform Standard (2012) Annex G example, 11.5 ga | 68° |
| Range on published pallet spec sheets | About 57 to 69° |
How it links to the other fields
The Uniform Standard (2012) Annex F relates the number of helixes (H) to thread length (Lt), flute count (F), thread crest diameter (Dt) and thread angle (At):
H = (Lt × F) ÷ (π × Dt × tan At)
For the PDS example (Lt 1.25 in, 4 flutes, Dt 0.124 in, 60°), H works out to about 7.4, close to the 7.5 on the sheet. H then feeds the withdrawal characteristic (Cw), which rates how well the thread grips. Pitch is thread length ÷ helixes (about 0.167 in here).
Why it matters
A nail with the right thread geometry turns as it is driven and locks into the wood. Thread angle, crest depth and flute count all change withdrawal resistance, so two nails of the same length and gauge can perform differently. Buyers rarely set thread angle directly; they specify a minimum Cw (FWC) or a proven nail, and the supplier's spec sheet shows the angle.
On a spec sheet
"Thread Angle" in the fastener table, next to flutes, helixes and pitch.
Related
- GlossaryHelically threaded nail (pallet)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.
- 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.
- 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.
- 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.
- 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.
More in Fasteners
- 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.
- 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.
- 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. 266 words.