Tooth Washer vs. Split Washer
Two old-school answers to vibration loosening: teeth that bite the mating surface, or a split ring that acts like a spring. Both are single-use cheap insurance — and both lose to a prevailing-torque nut or threadlocker where vibration is severe.
| Feature | Tooth Washer | Split Washer |
|---|---|---|
| How it locks | Teeth bite into the nut and surface | Split ends dig in under load |
| Best surface | Soft to medium metals | Soft to medium metals |
| Reusable | No — teeth flatten | Marginally — spring weakens |
| Vibration resistance | Moderate | Low to moderate |
| Finish damage | Visible teeth marks | Circular score marks |
| Extra duty | Doubles as a grounding washer (electrical) | None |
| Best for | Grounding lugs, light machinery | Cheap general-purpose insurance |
Verdict
Shop This Comparison
- Tooth lock washer assortment — internal + external tooth
- Split lock washer assortment — zinc-plated, multi-size
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Also in the toolbox
- Threadlocker (Loctite Blue 242) — when washers are not enough
FAQ
Do split lock washers actually work?
Less than their reputation. Testing shows a properly torqued joint with a flat washer resists loosening about as well — the split ring helps most on soft surfaces where the ends dig in. For real vibration, use a prevailing-torque nut or threadlocker.
Can you reuse lock washers?
A split washer survives one careful reuse if it still springs; a tooth washer does not — flattened teeth never bite again. Both cost pennies, so replacement is the pro move.
Internal vs. external tooth washers?
External teeth give a bigger bite and better grounding contact; internal teeth suit small screw heads and a neater appearance. Same rule either way: one use, then replace.
What should replace a lock washer?
A prevailing-torque (nylon or all-metal) nut, liquid threadlocker, or simply proper preload with a flat washer under the nut. All three outperform either washer style in vibration testing.