FF-W-84 — Washers, Lock (Spring)
FF-W-84 covers helical spring lock washers — split, helical-coiled washers that resist loosening of a bolted joint by maintaining spring tension and friction against the mating surfaces. Revision A dates to April 17, 1967; per later notices the document is inactive for new design but remains valid for use.
At a Glance
Overview
FF-W-84 describes a helical spring-type washer used with nuts, bolts, screws, and studs to prevent them from loosening. A helical spring lock washer is essentially a single coil of split, rectangular-section wire formed into a washer shape — when compressed under a bolted joint, its edges and two bearing surfaces bring spring tension and a frictional/biting locking principle into play that materially resists any tendency of the joint to turn or back off.
The specification is organized by material class and style/duty level. Revision A was approved April 17, 1967; later notices (2000 and 2013) confirm the document is now inactive for new design — meaning new engineering designs should consider other locking methods or current commercial standards — but that it remains valid for use, including for legacy replacement procurement.
Class & Style Reference
FF-W-84 organizes lock washers by material class, with duty-level styles within each class.
Full Class Table
| Class | Material | Available Styles |
|---|---|---|
| A | Carbon Steel | Light, Regular, Heavy, Extra Duty, Hi-Collar |
| B | Corrosion Resistant Steel (Magnetic) | Light, Regular, Heavy |
| C | Corrosion Resistant Steel (Non-Magnetic) | Light, Regular, Hi-Collar |
| D | Aluminum-Zinc Alloy | Medium |
| E | Phosphorous Bronze or Tin Brass | Light, Regular |
| G | Nickel-Copper-Aluminum Alloy (K-Monel) | Light |
FF-W-84 is inactive for new design but remains valid for use, including legacy replacement procurement. Some related military standards, such as NAS1640, MS35338, and MS21049, cover similar helical spring lock washer configurations and may be the preferred current reference depending on the application.
FF-W-84 — Frequently Asked Questions
What's the difference between the FF-W-84 classes?
Each class corresponds to a different base material — Class A is carbon steel, Classes B and C are corrosion resistant steel (magnetic and non-magnetic respectively), Class D is aluminum-zinc alloy, Class E is phosphorous bronze or tin brass, and Class G is K-Monel (nickel-copper-aluminum alloy).
Is FF-W-84 still used today?
It's marked inactive for new design, so new engineering work typically references a current commercial or military lock washer standard instead. However, FF-W-84 remains valid for use and is commonly referenced for legacy replacement parts.
What does "Hi-Collar" style mean?
A Hi-Collar spring lock washer has a taller cross-section than the standard "Regular" style, providing greater axial spring travel and load capacity for higher-vibration applications.
Need FF-W-84 Spring Lock Washers?
Ananka Fasteners supplies FF-W-84 spring lock washers across all classes with full material traceability.
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