Two Way Lock Nuts, Marine Grade
What are marine grade two way lock nuts? Two way lock nuts are all-metal prevailing-torque nuts that resist loosening through a deformed or specially formed thread section rather than a nylon insert, gripping the bolt from either direction of approach. With no nylon, they hold their lock at temperatures that would defeat a nyloc and reuse better. In marine service they come in 316 stainless. AlbanyCountyFasteners.com stocks these in 316 stainless steel.
Why choose an all-metal lock nut
The two way lock nut answers the two situations where a nylon insert falls short: heat and reuse. Because the locking action comes from the metal itself, a slightly deformed thread section that grips the bolt, there is no nylon to soften, so it holds its lock well above the roughly 250°F ceiling that limits a nyloc, making it the choice near engines, exhausts, and hot machinery. The all-metal design also tolerates repeated installation better than a nylon insert that wears with each use. The two way part means it grips regardless of which way it is threaded on, which eases installation. On marine equipment that runs hot or is serviced often, that combination is worth having. In 316 the whole nut, locking feature included, resists salt, so it suits corrosive and high-temperature marine service together. Use anti-seize to manage the higher running torque and prevent galling on stainless.
Why choose 316 stainless two way lock nuts
- All-metal locking with no nylon to soften or wear
- Holds its lock above the temperature limit of nyloc nuts
- Reuses better than a nylon insert nut
- Grips from either direction of installation
- 316 stainless resists salt in high-temperature marine service
Common applications
- Marine engine, exhaust, and hot machinery mounts
- Frequently serviced connections
- High-temperature marine equipment
- Vibrating joints beyond the nylon temperature limit
- Structural and mechanical marine assemblies
- Any hot or reused locking joint in salt exposure
Marine Two Way Lock Nut FAQs
How does an all-metal lock nut work?
A deformed or specially formed thread section grips the bolt as prevailing torque, resisting rotation by metal friction rather than a nylon insert. The two way design grips regardless of installation direction.
Why choose this over a nyloc?
For heat and reuse. With no nylon to soften, it holds its lock above the roughly 250°F nyloc limit, and the all-metal design tolerates repeated installation better than a wearing insert.
Does it need more torque to install?
Yes, prevailing-torque nuts run harder than plain nuts because the locking feature grips throughout. Use anti-seize on stainless to manage that and prevent galling.
Why 316 here?
316 resists chloride pitting, so the nut suits salt exposure, and because it is all-metal it also handles high temperature, making it a good fit where marine service is both corrosive and hot.
Can I reuse a two way lock nut?
Better than a nylon insert nut, since the metal locking feature does not wear as quickly. Inspect the prevailing torque and replace if it has dropped noticeably.
Do I still need thread locker?
Usually not; the nut provides a mechanical lock. Thread locker is optional redundancy for severe cases, but the all-metal lock is designed to resist loosening on its own.