Stainless Steel Nylon Insert Lock Nuts
What are nylon insert lock nuts? Stainless steel nylon insert lock nuts, often called nyloc nuts, have a nylon collar that grips the bolt threads to prevent loosening from vibration. Made from 18-8 and 316 stainless, they resist rust while keeping vibration-prone joints tight in wet and outdoor conditions.
How the nylon collar locks and its limits
The nylon ring inside the top of the nut has no threads until the bolt cuts into it, and that friction is what resists back-off under vibration. It is clean, needs no threadlocker, and is the most common all-purpose lock nut. Its main limit is heat: the nylon softens at higher temperatures, so for hot environments choose an all-metal lock nut instead. Nylon also wears with reuse, so fresh nuts are best on critical joints. Choose 18-8 for general use and 316 for coastal exposure.
Nylon insert vs all-metal lock nuts
- Nylon insert: clean, strong grip, best up to moderate temperatures.
- All-metal (two-way): better for high heat and reuse.
- Both: resist vibration far better than a standard nut.
Common applications for nylon insert lock nuts
- Machinery and equipment under vibration
- Automotive and trailer assembly
- Railings, playground, and outdoor structures
- Marine hardware (use 316)
For tight clearances, see stainless nylon insert jam lock nuts, and browse every lock nut style on the main lock nuts category.
Stainless Steel Nylon Insert Lock Nuts FAQ
What grades do nylon insert lock nuts come in?
18-8 and 316 stainless. Use 316 for coastal and saltwater exposure.
Are nylon insert lock nuts reusable?
They can be reused a few times, but the nylon wears and grips less each time. For a critical joint, use a fresh nut.
Do nylon insert nuts need threadlocker?
No. The nylon collar provides the locking action, so no threadlocker is needed, which keeps the joint clean and easy to remove.