Tab Washer
Washers · lock tab washer · tab lock washer · bearing lock washer
Definition: A tab washer is a thin washer with one or more tabs that bend up against the nut flat and down into a keyway or slot, positively locking the nut against rotation.
Anatomy & Schematic
■ Body■ Hole
Governing standards: Manufacturer specified (no universal standard)
Common Sizes
| Inch | Metric | Head width | Head height |
|---|---|---|---|
| for 1/2 | M12 | — | — |
| for 3/4 | M20 | — | — |
| for 1 | M24 | — | — |
Representative sizes. Full dimensional data lives in the standards listed below.
Grades & Strength
| Grade | Material | Tensile (psi) | Marking |
|---|---|---|---|
| Steel | steel | — | None |
| Stainless | stainless steel | — | None |
Materials
- Steel
- Stainless steel
Pros & Cons
Pros
- Positive mechanical lock
- Cheap
- No special nut needed
Cons
- Tabs are single-use
- Only works with keyed shafts
- Tabs can fatigue and crack
Typical Uses
- Bearing lock nuts
- Shaft retention
- Spindles
- Gear assemblies
Alternatives & Related
- Split Lock Washer — General anti-loosening ring
- Castle Nut — Positive lock with a cotter pin
- Prevailing Torque Nut — Friction lock without tabs
Where to Buy
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FAQ
What is a tab washer?
A washer with tabs that bend up against the nut and down into a slot, mechanically preventing the nut from loosening.
How do you install a tab washer?
Seat the inner tab in the shaft keyway or slot, tighten the nut, then bend the outer tab up against one flat of the nut.